High-Throughput Hyperspectral Imaging With Superior Resolution And Optical Sectioning

ABSTRACT

An imaging system includes a light source configured to illuminate a target and a camera configured to image light responsively emitted from the target and reflected from a spatial light modulator (SLM). The imaging system is configured to generate high-resolution, hyperspectral images of the target. The SLM includes a refractive layer that is chromatically dispersive and that has a refractive index that is controllable. The refractive index of the refractive layer can be controlled to vary according to a gradient such that light reflected from the SLM is chromatically dispersed and spectrographic information about the target can be captured using the camera. Such a system could be operated confocally, e.g., by incorporating a micromirror device configured to control a spatial pattern of illumination of the target and to modulate the transmission of light from the target to the camera via the SLM according to a corresponding spatial pattern.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/594,956, filed Jan. 12, 2015, which application is incorporatedherein by reference.

BACKGROUND

Unless otherwise indicated herein, the materials described in thissection are not prior art to the claims in this application and are notadmitted to be prior art by inclusion in this section.

A variety of methods exist to image biological tissues or othermaterials at the micro-scale (i.e., at scales at or smaller than a fewmicrometers). Such methods can include optical microscopy according to avariety of different illumination schemes and using optical systemsconfigured in a variety of different ways. Samples to be imaged could bebroadly illuminated (e.g., in bright-field microscopy), exposed to somestructured illumination (e.g., light sheet microscopy), exposed topolarized illumination (e.g., phase contrast microscopy), exposed toillumination at one or more specified points (e.g., confocalmicroscopy), or illuminated according to some other scheme. Conversely,light can be received and/or focused from the samples to be imaged in avariety of ways; light can be received from a wide field of the sampleand focused on an imager, subjected to an aperture (e.g., an aperturecorresponding to an aperture used to illuminate the sample as in, e.g.,confocal microscopy) before being imaged by an imager or light sensor,or received by some other means. Further, light of different wavelengthscan be used to illuminate a sample (e.g., to excite a fluorophore in thesample) and/or light of different wavelengths can be detected from thesample to determine spectrographic information (e.g., emission spectra,excitation spectra, absorbance spectra) about the sample or according tosome other application.

SUMMARY

Some embodiments of the present disclosure provide a system including:(i) a light source; (ii) a first camera, wherein the first cameraincludes a plurality of light-sensitive elements disposed on a focalsurface of the first camera; (iii) a spatial light modulator, whereinthe spatial light modulator includes a reflective layer disposed beneatha refractive layer, wherein the refractive layer is configured to have arefractive index that varies spatially across the spatial lightmodulator according to a controllable gradient, wherein at least thedirection and magnitude of the controllable gradient are electronicallycontrollable, and wherein the refractive layer is chromaticallydispersive; and (iv) an optical system, wherein the optical system isconfigured to (a) direct light from the light source to a target, (b)direct light emitted from the target in response to the light from thelight source toward the spatial light modulator, and (c) direct lightemitted from the target and reflected from the spatial light modulatorto the first camera such that the focal surface of the first camera isconjugate to a focal surface passing through the target.

Some embodiments of the present disclosure provide a system including:(i) illuminating means configured to emit light; (ii) first imagingmeans, wherein the first imaging means include a plurality oflight-sensitive elements disposed on a focal surface of the firstimaging means; (iii) a spatial light modulating means, wherein thespatial light modulating means include a reflective layer disposedbeneath a refractive layer, wherein the refractive layer is configuredto have a refractive index that varies spatially across the spatiallight modulating means according to a controllable gradient, wherein atleast the direction and magnitude of the controllable gradient areelectronically controllable, and wherein the refractive layer ischromatically dispersive; and (iv) optical means, wherein the opticalmeans are configured to (a) direct light from the illuminating means toa target, (b) direct light emitted from the target in response to thelight from the illuminating means toward the spatial light modulatingmeans, and (c) direct light emitted from the target and reflected fromthe spatial light modulating means to the first imaging means such thatthe focal surface of the first imaging means is conjugate to a focalsurface passing through the target.

Some embodiments of the present disclosure provide a method including:(i) illuminating, by a light source, a target, via an optical systemconfigured to direct light from the light source to the target; (ii)electronically controlling a spatial light modulator during a firstperiod of time such that a refractive layer of the spatial lightmodulator has a refractive index that varies spatially across thespatial light modulator according to a controllable gradient, whereinthe controllable gradient has at least a first specified direction and afirst specified magnitude, wherein the spatial light modulator furtherincludes a reflective layer disposed beneath the refractive layer, andwherein the refractive layer is chromatically disperse; (iii) imaginglight emitted from the target in response to the light from the lightsource during the first period of time using a first camera to produce afirst image of the target, wherein the first camera includes a pluralityof light-sensitive elements disposed on a focal surface of the firstcamera, wherein the optical system is further configured to direct lightemitted from the target in response to the light from the light sourcetoward the spatial light modulator and direct light emitted from thetarget and reflected from the spatial light modulator to the firstcamera such that the focal surface of the first camera is conjugate to afocal surface passing through the target; and (iv) determiningspectrographic information for a particular region of the target basedat least on the first image of the target.

These as well as other aspects, advantages, and alternatives, willbecome apparent to those of ordinary skill in the art by reading thefollowing detailed description, with reference where appropriate to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example imaging apparatus.

FIG. 2A illustrates a cross-section view of elements of an examplespatial light modulator.

FIG. 2B illustrates the dependence of refractive index on wavelength oflight of materials that could be incorporated into the spatial lightmodulator of FIG. 2A.

FIG. 2C illustrates reflection of light by the spatial light modulatorof FIG. 2A.

FIG. 2D illustrates reflection of light by the spatial light modulatorof FIG. 2A.

FIG. 2E illustrates reflection of light by the spatial light modulatorof FIG. 2A.

FIG. 3A illustrates an example environment that could be imaged.

FIG. 3B illustrates an example image of the environment of FIG. 3A.

FIG. 3C illustrates an example image of the environment of FIG. 3A.

FIG. 3D illustrates an example image of the environment of FIG. 3A.

FIG. 4A illustrates a cross-section view of elements of an examplemicromirror device reflecting laser light during a first period of time.

FIG. 4B illustrates a cross-section view of the elements of the examplemicromirror device of FIG. 4A reflecting laser light during a secondperiod of time.

FIG. 5A illustrates an example configuration of a micromirror device.

FIG. 5B illustrates an example focal surface of a camera illuminated bylight reflected from the micromirror device of FIG. 5A.

FIG. 5C illustrates an example focal surface of a camera illuminated bylight reflected from the micromirror device of FIG. 5A.

FIG. 5D illustrates an example focal surface of a camera illuminated bylight reflected from the micromirror device of FIG. 5A.

FIG. 6A illustrates a first configuration of an example micromirrordevice.

FIG. 6B illustrates an example focal surface of a camera illuminated bylight reflected from the micromirror device of FIG. 6A.

FIG. 6C illustrates a second configuration of the micromirror device ofFIG. 6A.

FIG. 6D illustrates an example focal surface of a camera illuminated bylight reflected from the micromirror device of FIG. 6C.

FIG. 7A illustrates an example imaging apparatus.

FIG. 7B illustrates an example timing diagram for operation of elementsof the imaging apparatus of FIG. 7A.

FIG. 8 is a functional block diagram of an example imaging system.

FIG. 9 is a flowchart of an example method.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying figures, which form a part hereof. In the figures, similarsymbols typically identify similar components, unless context dictatesotherwise. The illustrative embodiments described in the detaileddescription, figures, and claims are not meant to be limiting. Otherembodiments may be utilized, and other changes may be made, withoutdeparting from the scope of the subject matter presented herein. It willbe readily understood that the aspects of the present disclosure, asgenerally described herein, and illustrated in the figures, can bearranged, substituted, combined, separated, and designed in a widevariety of different configurations, all of which are explicitlycontemplated herein.

Further, while embodiments disclosed herein make reference to use on orin conjunction with samples of tissue extracted from a human body, it iscontemplated that the disclosed methods, systems and devices may be usedin any environment where spectrographic imaging and/or opticalsectioning of other tissues or other objects or elements of anenvironment is desired. The environment may be any living or non-livingbody or a portion thereof, a work piece, an implantable device, amineral, an integrated circuit, a microelectromechanical device, etc.

I. Overview

A variety of microscopy techniques can be applied to determineinformation about the structure of biological tissues or othermaterials. Such information can include information about the location,shape, size, or other information about elements of a target (e.g., thelocation, shape, and/or spectral properties of fluorophores, proteins,cells, or other contents in a sample of biological tissue). Thesetechniques generally include illuminating a target, receiving lightresponsively emitted from the target, and presenting the received lightto a light sensor (e.g., a camera) such that one or more images or otherinformation about the target can be determined.

A variety of optical systems can be used to present illumination to thetarget (e.g., to present illumination to specified portions of thetarget) and/or to direct light emitted from the target to a light sensor(e.g., to present light from a focal plane on or within the target tolight-sensitive elements arranged on a focal plane of a camera). Systemsconfigured to microscopically image a target can be configured tomaximize a spatial resolution (e.g., a minimum resolvable distancebetween features and/or elements of a target) and/or a temporalresolution (e.g., a rate in time at which images of a target can begenerated) of imaging data generated about a target, to minimize anamount of light used to generate images (e.g., to prevent photobleachingor other light-induced effects on a target), or to optimize some otherproperty according to an application.

In some examples, spectrographic information about a target could bedetected and/or determined. Spectrographic information could include anyinformation about the dependence of the absorbance, reflectance,excitation, emission, or some other interaction of elements or featuresof a target with light applied to the target (e.g., visible, infrared,or ultraviolet light) on the wavelength of the applied and/or emittedlight. That is, spectrographic information could include one or more ofan absorbance spectrum, a reflectance spectrum, an excitation spectrum,an emission spectrum, or some other spectrum detected and/or determinedfor a plurality of wavelengths. For example, spectrographic informationcould include a spectrum of light (e.g., a plurality of detectedamplitudes corresponding to the amplitudes of light received in aplurality of respective ranges of wavelengths) emitted from a particularportion (e.g., an element or feature) of a target response toillumination of the portion of the target by light (e.g., bymonochromatic light).

Such spectrographic information could be accessed by imaging the targetusing a color camera or otherwise filtering and/or separating lightreceived from the target according to wavelength (e.g., using one ormore dielectric mirrors). Additionally or alternatively, light from thetarget (e.g., from a particular point or other specified portion of thetarget) could be passed through or otherwise affected by a chromaticallydispersive element (e.g., a prism) configured to selectively affectdifferent wavelengths of light (e.g., to reflect and/or refractdifferent wavelength of light at corresponding different angles). Forexample, a beam of light emitted from a particular portion of a targetcould be directed through a prism of a spectrometer, and thespectrometer could be operated to determine spectrographic information(e.g., a spectrum) of the beam of light. In some examples, a spatiallight modulator could be configured to have one or more electronicallycontrollable optical properties (e.g., a refractive index, a degree ofchromatic dispersion) that can be controlled to enable the detectionand/or determination of spectrographic information from light receivedfrom a target.

In some examples, such a spatial light modulator (SLM) could include arefractive layer disposed on a reflective layer. The refractive layercould be electronically controllable to have a refractive index thatvaries spatially across a surface of the SLM according to a controllablegradient (e.g., a substantially linear gradient). Further, thecontrollable refractive index of the refractive layer could bechromatically disperse, i.e., dependent on the wavelength of lightrefracted by the refractive layer. A magnitude, direction, or otherproperty of the controllable gradient in the refractive index of the SLMcould be controlled according to an application, e.g., to control anangle of reflection of light incident on the SLM, to control a degree ofspectral dispersion of light reflected from the SLM (e.g., to control aspectral resolution at which an imager receiving the dispersed lightcould determine spectrographic information for the light reflected formthe SLM), or according to some other application.

Spectrographic information could be determined for a particular portionof a target by reflecting a beam of light from the particular portionfrom such an SLM to a camera. The camera could be operated to detect theintensity of the beam of light at different wavelengths usingcorresponding different light-sensitive elements of the camera.Additionally or alternatively, a plurality of images of the target couldbe taken using light reflected from the SLM during a respective periodsof time when the SLM is operated to have respective different refractiveindex patterns (e.g., substantially linear gradients having respectivedirections and/or magnitudes) and spectrographic information about thetarget could be determined based on the plurality of images, e.g., by aprocess of deconvolution.

An SLM could include a chromatically dispersive liquid-crystal layerhaving refractive index that depends on a magnitude of electrical fieldor time-varying electrical signal applied to the liquid-crystal. The SLMcould include a plurality of electrodes disposed on one or both sides ofthe liquid-crystal layer such that the refractive index of the SLM couldbe controlled according to a variety of patterns (e.g., a substantiallylinear gradient having a specified direction and magnitude). Forexample, the SLM could have a first transparent electrode opposite thereflective layer and a plurality of regularity-spaced electrodes (e.g.,according to a rectangular grid) disposed on or within the reflectivelayer. Voltages between the first electrode and each of the plurality ofregularly-spaced electrodes could be controlled to control therefractive index of corresponding regions (e.g., cells) of therefractive layer disposed between the first electrode and each of theplurality of regularly-spaced electrodes.

A microscope or other imaging system could include such an SLM and beconfigured to provide hyperspectral confocal imaging, e.g.,spatially-sectioned imaging that additionally generates spectrographicinformation about regions of an imaged target. This could includeplacing an SLM into the path of light received from a target by aconfocal microscope before that light is imaged, e.g., after thereceived light passes through an aperture (e.g., an aperture thatoptically corresponds to an aperture through which a light sourceilluminates the target). In some examples, a system could include an SLMand a micromirror device configured to control a pattern of illuminationof a target by a light source. The micromirror device could furthercontrol a pattern of light that is received in response from the targetand that is presented, via the SLM, to an imager. Such a micromirrordevice could be controlled to illuminate, and to receive light from,single portions of a target at a time (e.g., by controlling a singlemicromirror of the micromirror device to reflect illumination from thelight source toward a corresponding portion of the target, andconversely to reflect light responsively emitted from correspondingportion of the target, via the SLM, to a camera) and to scan across thetarget (by sequentially activating particular micromirrors of themicromirror device) to generate a hyperspectral image of the target.Such a micromirror device could additionally or alternatively beoperated according to some other method, e.g., to effect a Hadamard orother coded aperture in the reflection of light from the light source tothe target or to illuminate a number of spatially separate portions ofthe target by controlling a corresponding number of spatially separatemirrors of the micromirror device.

Additionally or alternatively, an SLM and corresponding camera could beconfigured to generate spectrographic information (e.g., hyperspectralimages) for a confocally-imaged target using non-conjugate light emittedfrom the target (i.e., light emitted from portions of the target that donot correspond to apertures of the imaging apparatus that includes theSLM and camera). For example, an imaging system could include amicromirror device, a light source, a first camera, and an opticalsystem configured such that the micromirror device can be operated tocontrol which portion(s) of a target is illuminated by the light source(e.g., by controlling a corresponding micromirror to reflect light fromthe light source toward the portion of the target) and from whichportion(s) light will be reflected toward the first camera, via themicromirror device, to allow the first camera to detect a confocal imageof the portion of the target (and of the entire target if themicromirror device is operated to sequentially illuminate differentportions of the target, e.g., by operating the micromirrors to scan theillumination across the target). The imaging system is furtherconfigured such that light that is not reflected toward the first camerais reflected, in-focus, to a second camera via an SLM. Taking multipleimages with both the first and second cameras (e.g., images taken whilethe micromirror device is operated to sequentially illuminate eachportion of the target with light reflected from the light source) couldallow for multiple confocal images to be taken of the target (e.g., themultiple images taken by the first camera) and for a singlehyperspectral image (or other spectrographic information about thetarget) to be determined based on the multiple images taken by thesecond camera (e.g., via a process of deconvolution).

Spectrographic information (e.g., hyperspectral microscopic images)determined about a target using the systems and/or methods herein couldbe used to enable a variety of applications. Detecting an emissionspectrum, excitation spectrum, absorption spectrum, color, or otherspectrographic information about elements and/or features of a targetcould allow for the identification of the elements and/or features ofthe target (e.g., determining that a feature is a particular protein,based on a correspondence between determined spectrographic informationfor the feature and known spectrographic information for the particularprotein). Additionally or alternatively, one or more properties of anelement or feature of the target (e.g., an oxidation state, a local pH,a conformation, a state of binding to a ligand) could be determinedbased on determined spectrographic information for the element orfeature (e.g., based on a center frequency, width, amplitude, shape, orother property of a peak or other feature of a determined absorption,emission, excitation, or other spectrum of the element or feature).

In some examples, spectrographic information determined about a targetusing the systems and/or methods herein could be used to determine thelocation, properties, identity, and other information about fluorophoresin a target. Such fluorophores could be naturally present in the targetor could be introduced via staining, genetic manipulation (e.g., theaddition of a green fluorescent protein gene to another gene of interestin an organism), or some other method. Targets could be imaged, and thelocation of such fluorophores in such targets determined, byilluminating the target with light at an emission wavelength of thefluorophores. Spectrographic information could be determined for thetarget (e.g., for portions of the target containing such fluorophores)and used to determine the identity of individual fluorophores in thetarget (e.g., by determining that an emission spectrum of an imagedfluorophore corresponds to the emission spectrum of one of a set offluorophores present in the target). Additionally or alternatively,information about the state of the fluorophore (e.g., an oxidationstate, a local pH, a conformation, a state of binding to a ligand) couldbe determined based on determined spectrographic information for thefluorophore.

Other configurations, modes and methods of operation, and otherembodiments are anticipated. Systems and/or methods described hereincould include additional microscopic or other imaging modalities and/oroptical systems or elements to improve the identification of thecontents of portions of a target according to an application. A systemas described herein could include multiple light sources, multiplespatial light modulators, multiple cameras, multiple micromirrordevices, and/or additional components according to an application.Systems and methods described herein could be used to add hyperspectraland/or spectrographic imaging capabilities to a variety of othermicroscopic or other imaging systems. Further, systems and methods asdescribed herein could be configured or operated according to and/or incombination with a variety of different microscopic or other imagingtechniques, e.g., stimulated emission depletion, ground state depletion,saturated structured illumination microscopy, 4pi imaging,photobleaching, or other methods or techniques.

Systems or methods described herein could be applied toward imagingand/or determining spectrographic information about biological tissue orsome other type of target. For example, systems and methods describedherein could be used to hyperspectrally image materials, alloys, ores,minerals, textiles, microfluidic systems, chemical and/or pharmaceuticalproducts, manufactured nanostructures (e.g., integrated circuits and/ormicroelectromechanical systems) or other types of targets. Otherapplications and configurations of systems as described herein areanticipated.

It should be understood that the above embodiments, and otherembodiments described herein, are provided for explanatory purposes, andare not intended to be limiting.

II. Example Imaging Apparatus and Example Spatial Light Modulator

A variety of applications include imaging a target (e.g., a biologicalsample, a mineral, an integrated circuit, a material surface, a surfacecoating) at a very small scale. In some applications, it could beadvantageous to detect spectrographic information about the target,e.g., to detect an excitation spectrum, an emission spectrum, anabsorption spectrum, a reflection spectrum, a scattering spectrum, acolor, or some other spectrum or other wavelength-dependence ofinteraction with light of one or more portions (e.g., proteins, cells,or other elements) of the target. Such detected spectrographicinformation could allow the identification of elements of the target(e.g., by comparing detected spectrographic information from a portionof the target to a database of spectrographic information correspondingto a plurality of potential contents of the target), to allowidentification of properties of the target (e.g., to detect a pH in thetarget based on a detected pH-dependent spectrographic property of oneor more elements of the target), or to allow some other application.

Imaging a target at a small scale (e.g., at a scale able to resolveindividual features having dimensions less than one micron, orpreferentially less than 100 nanometers) could allow for detection ofsmaller elements or features of the target (e.g., individual cells,individual processes of cells, individual proteins). Imaging the targetat a high sample rate (i.e., producing an individual image in a shortperiod of time) could allow the detection of time-dependent processes inthe target (e.g., the motion of cell or proteins, changes in thespectrographic properties of a protein due, e.g., to binding andun-binding of the protein with a ligand or analyte). For example,imaging the target at high spatial and temporal resolution (i.e., toresolve very small elements or features of the target during shortperiods of time) while exposing the target to a minimum of visiblelight, ultraviolet radiation, infrared radiation, or other illuminationmay prevent causing damage to the sample and may avoid photobleachingelements (e.g., fluorophores) of the sample.

Imaging a target can include illuminating the target, receiving lightresponsively emitted from the target (through fluorescent absorption andemission, reflection, scattering, refraction, Raman scattering, or someother interaction between the light and elements of the target), andgenerating an image of the target based on the received light. Suchillumination and/or reception of light can be of/from a wide area of thetarget (e.g., bright-field microscopy) or of/from some specified regionof the target (e.g., a plurality of specified small volumes of thetarget, as in confocal microscopy). Spectrographic information could bedetected/determined for one or more regions of the target byilluminating the target with multiple lights having multiple respectivespectrographic properties (e.g., containing light at multiple respectivewavelengths) and/or by detecting a wavelength-dependence of theamplitude or other properties of the received light (e.g., by detectingthe amplitude of the received light within multiple ranges ofwavelengths).

A variety of methods could be employed to determine spectrographicinformation of light received from a target. In some examples, lightreceived from a target could be filtered and/or reflected according towavelength (e.g., using a dichroic filter, a dielectric mirror, a gelfilter, a Bragg mirror) such that the amplitude or other properties ofthe received light in one or more specified ranges of wavelengths couldbe detected. For example, a color camera could include a plurality ofred, green, and blue filters configured to filter received light that isdirected to respective light-sensitive elements (e.g., pixels) of thecamera, allowing the use of the color camera to detect spectrographicinformation from the received light. In some examples, the receivedlight could be applied to a chromatically dispersive element (i.e., anelement having one or more optical properties that arewavelength-dependent) such that portions of the light at differentwavelengths could be differently reflected, refracted, absorbed, orotherwise interacted with to allow detection of spectrographic contentsof the received light. For example, the received light could be passedthrough an optical element (e.g., a prism) having a refractive indexthat is wavelength-dependent, such that different wavelengths of thereceived light are refracted differently, e.g., in different directions.In some examples, the received light could be transmitted through orreflected from a diffraction grating configured to transmit or reflectlight at different wavelengths in different directions, or to separate,filter, or otherwise interact with the light in a wavelength-dependentmanner such that spectrographic content of the received light could bedetected. Other methods and/or systems could be used to separate, block,filter, or otherwise manipulate light received from a target in order todetect and/or determine spectrographic information about the receivedlight and/or about the target.

FIG. 1 illustrates in cross-section elements of an example imagingsystem 100 configured to image a target 105. The system 100 includes alight source 120 (e.g., a laser), a camera 130 (illustrated as a planeof light-sensitive elements located on a focal plane 137 of the camera130), a micromirror device (MD) 150 (in which the micromirrors arelocated on a focal plane 157), a spatial light modulator (SLM) 110, andan optical system (including an objective 141, first 143 and second 144relay lenses, a dichroic mirror 145, and an optical sink 125) configuredto direct light to and from the target 105 and between the elements ofthe system 100. The system 100 additionally includes a stage 160 towhich the target 105 is mounted. Note that the MD 150 and camera 130comprise two-dimensional arrays of micromirrors and light-sensitiveelements, respectively. Further, note that the optical system (e.g.,141, 143, 144, 145) and SLM 110 are configured to direct light betweenthe target, 105, MD 150, and camera 130 such that locations on the focalsurfaces 157, 137 of the MD 150 and camera 130 correspond to respectivelocations on the focal surface 107 in the target 105.

The system 100 illuminates a specified region 109 on a focal surface 107in the target 105 by emitting a first illumination 121 from the lightsource 120 and reflecting the first illumination 121 from the dichroicmirror 145 toward the MD 150. A selected mirror 151 of the MD 150 thathas a location on a focal surface 157 of the MD 150 corresponding to thespecified region 109 is controlled to reflect the first illumination 121toward the target 105 as in-focus illumination 122 via the objective141. Other mirrors 153 of the MD 150 are controlled to reflect theremainder of the first illumination 121 as waste illumination 123 towardthe optical sink 125 to be absorbed. As illustrated, a single mirror(151) is controlled to illuminate (and to receive light from) acorresponding region 109 of the target 105; however, additional mirrors(e.g., selected from other mirrors 153) could be operatedsimultaneously, sequentially, or according to some other scheme toilluminate (and to receive light from) corresponding additional regionsof the target 105.

The system 100 receives light (including conjugate light 132) emittedfrom the specified region 109 in response to illumination via theobjective 141. The conjugate light 132 arrives, in-focus, at theselected mirror 151 and is reflected (through the dichroic mirror 145)toward the SLM 110. The first relay lens 143 (and/or some other opticalelements of the system 100) collimates the received light and presentsthe substantially collimated light to the SLM 110. The SLM 100 reflectsthe conjugate light 132 as spectrally dispersed light 133 toward thesecond relay lens 144 that is configured to present the spectrallydispersed light 133 in-focus to a specified region 131 on a focalsurface 137 of the camera 130 corresponding to the specified region 109(e.g., to a region of the camera having one or more light-sensitiveelements and/or pixels of the camera 130). The SLM 110 is configuredand/or operated such that the spectrally dispersed light 133 isspectrally dispersed relative to the conjugate light 132 in a controlledmanner such that spectrographic information of the particular region 109and/or of the conjugate light 132 can be detected or determined. In someexamples, the spectrally dispersed light 133 is spectrally dispersed ina manner related to an electronically controlled direction, magnitude,and/or some other property of a spatial gradient in the refractive indexof a layer of the SLM 110.

Note that the system 100 and elements thereof shown in FIG. 1 areintended as a non-limiting example of systems and methods as describedelsewhere herein for generating hyperspectral or otherwisespectrographic images of a target (e.g., 105). Imaging systems couldinclude more or fewer elements, and could image a target according tosimilar or different methods. As shown, the system 100 can be operatedto image the target 105 confocally; i.e., to illuminate a specifiedregion of the target 109 in-focus and to receive light responsivelyemitted from the specified region 109 in-focus using the micromirrordevice 150 (e.g., to control the spatial pattern of light emitted towardand received from the target 105). Illumination could be delivered tothe target 105 and light received from the target 105 in different waysand using differently configured elements (e.g., different optics). Thetarget 105 could be illuminated along an optical path separate from theoptical path used to receive light responsively emitted from the target105. For example, illumination could be transmitted through a targetbefore being received to image the target. Particular regions of thetarget 105 could be illuminated, and light received from such regions,by steering a beam of illumination using one or more controllablemirrors, lenses, diffraction gratings, or other actuated opticalelements.

An SLM (e.g., 110) as described herein could be configured and operatedas part of a variety of different imaging systems (e.g., bright-fieldmicroscopes, 4-pi microscopes, confocal microscopes, fluorescencemicroscopes, structured illumination microscopes, dark fieldmicroscopes, phase contrast microscopes) to provide controlled spectraldispersion of light for a variety of applications (e.g., to allowhyperspectral or otherwise spectrographic imaging of a target). Forexample, an SLM as described herein could be inserted into the path oflight received by some other variety of microscope or imager (e.g., abright-field microscope). The SLM could be operated to have a pluralityof different specified magnitudes and/or directions of refractive indexgradient across the SLM during a respective plurality of periods oftime, and such an imager could be configured to generate a plurality ofimages of the received light reflected from the SLM during the pluralityof periods of time. In such examples, spectrographic information about aparticular portion of a target (e.g., a target from which the receivedlight is received) could be determined based on a plurality of detectedamplitudes (or other properties of light) of pixels across the pluralityof images according to a model (e.g., a black-box model fitted tocalibration data for the imager) or other description of therelationship between the detected amplitudes and spectrographicproperties of regions of the target depending on the configuration ofthe SLM (e.g., via a process of deconvolution performed on the pluralityof images and based on a wavelength-dependent point-spread functiondetermined for the imager). Further, an SLM as described herein could beused to control a direction and/or spectral content of a beam ofillumination, e.g., to effect a tunable light source in combination witha source of broad-spectrum light and, e.g., an aperture.

The light source 120 could include a variety of light-emitting elementsconfigured to produce illumination 121 having one or more specifiedproperties (e.g., specified wavelength(s)). This could include lasers,light-emitting diodes (LEDs), or other substantially monochromatic lightsources. Additionally or alternatively, the light source 120 couldinclude a light emitting element that emits light across a wider rangeof wavelengths (e.g., an arc lamp). In some examples, thisnon-monochromatic light could be emitted through one or more filters(e.g., filters including one or more Bragg reflectors, prisms,diffraction gratings, slit apertures, monochromators) configured to onlyallow the transmission of light within a narrow range of wavelengths. Insome examples, the light source 120 could be configured to emit light ata specified wavelength or having some other specified property to excitea fluorophore in the target 105 or to otherwise selectively interactwith (e.g., excite, quench, photobleach) one or more elements of thetarget 120. For example, the illumination 121 could include light atsubstantially one wavelength (i.e., could contain light of wavelengthswithin a specified narrow range of wavelengths) corresponding to anexcitation wavelength of a fluorophore (e.g., a green fluorescentprotein, a dsRED protein) in the target 105.

In some examples, the light source 120 could include a tunable laser orsome other light-emitting element(s) controllable to emit light at anyof a plurality of different wavelengths (e.g., wavelengths rangingbetween approximately 400 nanometers and approximately 2.5 micrometers).Such a tunable laser could include an excimer laser, a dye laser, a CO₂laser, a free-electron laser, or some other laser element configured toemit light at a plurality of different, controllable wavelengths. Insome examples, the wavelength of the light emitted by such a tunablelaser could be controlled by controlling a geometry or size of one ormore elements (e.g., a reflector, a resonating cavity) of the tunablelaser. In some examples, a Bragg reflector or other element of the lightsource 120 (e.g., of a tunable laser) could be rotated or otherwiseactuated to control the wavelength of light emitted by the light source120. In some embodiments, the light source 120 could include a pluralityof lasers or other sources of substantially monochromatic lightconfigured to emit light at wavelengths corresponding to respectivedifferent wavelengths (e.g., excitation wavelengths of respectivefluorophores in the target 105), and operation of the light source 120to emit light of a particular wavelength could include operating thecorresponding laser of the light source 120 to emit light at thecontrolled wavelength. Other configurations and operations of a lightsource 120 are anticipated.

The camera 130 could include a plurality of light-sensitive elementsdisposed on the focal surface 137. The light-sensitive elements could beconfigured to detect the amplitude or other properties of light receivedby the camera 130 across a broad range of wavelengths (e.g., across arange of wavelengths of light that can be emitted by elements of thetarget 105, e.g., a range that includes emission wavelengths of one ormore fluorophores in the target 105). That is, the camera 130 could beconfigured to act as broadband monochrome camera, receiving light fromthe target 105 (via, e.g., the SLM 110, MD 150, and optical system)during a plurality of periods of time and outputting a respectiveplurality of images related to the absorption, fluorescent re-emission,or other interactions of the target 105 with light (e.g., light of acorresponding plurality of wavelengths) emitted by the light source 120during a the respective plurality of periods of time. This could includethe camera 130 containing a regular two-dimensional (or otherwisearranged) array of light sensitive elements (e.g., photodiodes,phototransistors, pixels of a charge-coupled device (CCD), active pixelsensors) disposed on the focal surface 137 configured such that theoutput of an individual light sensitive element is related to theamplitude of the light received by the camera 130 from a particulardirection and at a particular wavelength (corresponding to a particularportion of the target 105 and the configuration of the SLM 110 and/or MD150).

Spectrographic information about a particular portion of the target 105(e.g., 109) could be determined based on a plurality of detectedamplitudes (or other properties of light) detected by a particular setof pixels (or other light sensitive elements) of the camera 130 (e.g.,pixels proximate to the specified region 131) when the system 100 isoperated and/or configured similarly to FIG. 1, i.e., to illuminate andto receive light from a particular region (e.g., 109) of the target 105(or from a plurality of such specified regions that are spatiallyseparate, such that individual pixels of the camera 130 receive lightfrom only one such region). Additionally or alternatively, a pluralityof images could be captured using the camera 130 during respectiveperiods of time when the SLM 110 and MD 150 are operated according torespective different configurations (e.g., different specifiedmagnitudes and/or directions of refractive index gradient across the SLM110, different sets of controlled angles of the mirrors 151, 153 of theMD 150). In such examples, spectrographic information about a particularportion of the target 105 (e.g., 109) could be determined based on aplurality of detected amplitudes (or other properties of light) detectedby a variety of pixels across the plurality of images according to amodel (e.g., a black-box model fitted to calibration data for the system100) or other description of the relationship between the detectedamplitudes and spectrographic properties of regions of the target 105depending on the configuration of the SLM 110 and MD 150 (e.g., via aprocess of deconvolution performed on the plurality of images and basedon a wavelength-dependent point-spread function determined for thesystem 100). Other configurations and/or operations of the system 100 toenable the detection and/or determination of spectrographic informationfor one or more regions of a target are anticipated.

Note that the configuration and/or operation of the system 100 toilluminate and to receive light from a specified region 109 on a focalsurface 107 of the target 105 is intended as a non-limiting example.Alternatively, a larger and/or differently-shaped region of the target(e.g., a line within the target; substantially the entire target and/orthe entire target within a field of view of the imaging system) could beilluminated by operating the mirrors 151, 153 of the MD 150 according toa different set of controlled angles than those illustrated. Forexample, a plurality of spatially separated regions proximate to thefocal surface 107 of the target 105 could be illuminated and imagedsimultaneously by controlling a corresponding plurality of spatiallyseparated mirrors of the MD 150 to reflect the first illumination 121toward the plurality of the regions of the target 105. The mirrors 151,153 of the MD 150 could be controlled according to some other pattern,e.g., to approximate some other coded aperture on the focal surface 157of the MD 150. Further, the light source 120 could emit illumination ata controllable wavelength (e.g., illumination that is substantiallymonochromatic, but having a wavelength that can be altered by operationof the light source) and spectrographic information could be determinedfor regions of the target 105 based on images of the target 105generated when the target 105 is illuminated by different wavelengths oflight (e.g., to generate a corresponding plurality of emission spectrafor the region corresponding to the different wavelengths ofillumination).

Further, note that the location of the focal surface 107 within thetarget 105 could be controlled (e.g., to allow imaging of elements ofthe target 105 at different depths within the target 105). In someexamples, the stage 160 could be actuated relative to other elements ofthe system 100 (e.g., relative to the objective 141) such that alocation of the target 105 in one or more dimensions could becontrolled. For example, the stage 160 could be actuated in a directionparallel to the direction of the conjugate illumination 132 (i.e., inthe vertical direction of FIG. 1) such that the location (e.g., thedepth) of the focal surface 107 within the target 105 could becontrolled. In such an example, a plurality of images and/orspectrographic information could be detected/determined of the target105 when the focal surface 107 is controlled to be at variety ofrespective locations (e.g., depths) within the target 105, allowing a3-dimensional image of the target 105 to be generated from the pluralityof images and/or spectrographic information. In some examples, thelocation of the particular region 109 on the focal surface 107 withinthe target 105 could be controlled by actuating the stage 160 to controlthe location of the target 105 relative to the system. Actuation of thestage 160 could include one or more piezo elements, servos motors,linear actuators, galvanometers, or other actuators configured tocontrol the location of the stage 160 (and a target 105 mounted on thestage 160) relative to element(s) (e.g., 141) of the system 100.

The imaging system 100 (or other example imaging and/or microscopysystems described herein) could include additional elements orcomponents (not shown). The imaging system 100 could include one or morecontrollers configured to operate the SLM 110, light source 120, camera130, MD 150, actuator(s) configured to control the location of the stage160, and/or other elements of the imaging system 100. The imaging system100 could include communications devices (wireless radios, wiredinterfaces) configured to transmit/receive information to/from othersystems (e.g., servers, other imaging devices, experimental systems,sample perfusion pumps, optogenetic or other stimulators) to enablefunctions and applications of the imaging system 100. For example, theimaging system 100 could include an interface configured to presentimages of the target 105 generated by the imaging system 100. Theimaging system 100 could include an interface configured to presentinformation about the imaging system 100 to a user and/or to allow theuser to operate the imaging system 100 (e.g., to set a spectrographicresolution, to set a spatial resolution, to set a temporalresolution/imaging sample rate, to set an operational mode (e.g.,conjugate or non-conjugate confocal imaging, bright-field imaging,stimulated emission depletion (STED) imaging), so set a maximum emittedillumination power, to set a range of wavelengths of interest).

Additionally or alternatively, the imaging system 100 (or other exampleimaging systems described herein) could be configured to communicatewith another system (e.g., a cellphone, a tablet, a computer, a remoteserver) and to present a user interface using the remote system. In someexamples, the imaging system 100 could be part of another system. Forexample, the imaging system 100 could be implemented as part of anelectrophysiological experimentation system configured to apply optical,electrical, chemical, or other stimuli to a biological sample (e.g., asample of cultured or extracted neurons). The imaging system 100 couldprovide information about changes in the configuration of the biologicalsample in response to stimuli (e.g., by determining spectrographicinformation about the tissue related to the presence and/or location ofcalcium in cells of the sample, e.g., by detecting fluorescentproperties of calcium indicators in the sample) and/or could provideinformation to inform to delivery of stimuli. In some examples, theimaging system 100 could include multiple SLMs 110, light sources 120,cameras 130, MDs 150, or other additional components. The imaging system100 could include sensors and/or be in communication with sensorsconfigured to image other properties of a target environment (e.g.,105). Other configurations, operations, and applications of imagingsystems as described herein are anticipated.

Spectrographic information about a biological tissue, cell, organelle,protein, chemical, fluid, fluorophore, mineral, integrated circuit,microelectromechanical device, or other portion of a target could bedetected and/or determined by illuminating the portion of the target,detecting light that is emitted from the portion in response to theillumination, and determining some spectrographic information about thereceived light. Determining spectrographic information could includegenerating a spectrum (e.g., a reflectance spectrum, an emissionspectrum, an absorbance spectrum) from the received light by detectingthe a plurality of amplitudes of the received light within a respectiveplurality of ranges of wavelengths. That is, the spectrographicinformation could include a plurality of detected and/or determinedamplitudes corresponding to wavelengths of the received light, e.g., atspecified wavelengths linearly spaced within a range of wavelengths.Such determined spectrographic information could be generated related tothe illumination of the target by light of a single wavelength.Alternatively, such spectrographic information could be determined aplurality of times corresponding to illumination of the target during arespective plurality of different periods of time by light of arespective plurality of different single wavelengths.

Spectrographic information could include a description of one or morefeatures of a spectrum or other wavelength-dependent optical propertiesof the target; for example, spectrographic information could include anabsolute or relative amplitude, mean wavelength, width at half maximum,or other descriptive information about a peak or other feature of aspectrum of a portion of a target. Such spectrographic information couldbe determined based on a determined and/or detected spectrum (e.g., byextracting an amplitude, width, or wavelength location of a peak withina determined and/or detected plurality of detected amplitudescorresponding to wavelengths of light received from the target).Alternatively, such spectrographic information could be determined inother ways, e.g., through an iterative process that includes controllingan SLM to increase a spectral resolution of an imaging system within arange of wavelengths that includes a peak or other feature of interestof a spectrum. Other types of spectrographic information and methods ofdetecting and/or determining such spectrographic information areanticipated.

In some examples, a fluorophore, chromophore, pigment, dye, coating, orother substance could be added to a target (e.g., a biological sample)according to an application (e.g., to mark one or more proteins,chemicals, or other elements of interest in the target). For example, afluorophore configured to selectively interact with an analyte (e.g.,with an enzyme, protein, marker, or other element expressed by cancercells) could be introduced into a biological sample such that theanalyte could be detected, localized, and/or identified in the sampleusing methods as described herein. Such identification could beperformed to determine the location, distribution, concentration, orother information about the analyte. In some examples, multiple suchfluorophores configured to interact with respective analytes could beadded to the target. A spectral resolution (e.g., a difference inwavelength between the wavelengths of light corresponding to detectedlight amplitudes of a spectrum or other detected or determinedspectrographic information) of an imager as described herein could bespecified to allow identification of the multiple fluorophores. Forexample, the spectral resolution could be specified such that two ormore peaks in a detected spectrum (e.g., an emission spectrum)corresponding to respective two or more fluorophores in the target couldbe distinguished (allowing, e.g., the determination of which of the twoor more fluorophores are present in a particular region of the target).In some examples, one or more of such fluorophores could be alreadypresent in the target, e.g., a fluorescent mineral, a fluorescentprotein naturally present in a biological sample, a fluorescent proteinpresent in a biological sample due to genetic manipulation of the sampleand/or an organism from which the sample is taken.

The identity of an element of a target (e.g., a particular region, aprotein, a cell, a mineral, a chemical) could be determined based onfeatures or other information about the spectrographic informationdetermined for the element. For example, the amplitude, centerfrequency, shape, presence, or other information about a peak in adetermined spectrum could indicate that the element comprises aparticular fluorescent protein, mineral, chemical, or other substance orstructure. In some examples, the identity and/or contents of an elementof a target could be determined by applying a classifier, model, orother algorithm to detected or determined spectrographic information forthe element. For example, a vector of values representing a determinedemission spectrum for the element (e.g., individual values of the vectorrepresent amplitudes of light received from the element withincorresponding ranges of wavelengths) could be applied to a k-means,k-nearest neighbor, neural net, support vector machine, decision tree,or other variety of classifier. Other distinctions and/oridentifications of regions of a target, based on additional oralternative features of a spectrum of the regions, are anticipated.

Additionally or alternatively, an introduced and/or already-presentfluorophore, chromophore, pigment, dye, coating, or other substancecould have one or more spectrographic properties (e.g., an amplitude,center wavelength, width, or other property of a peak within anabsorption or other spectrum of the introduced substance) that arerelated to properties (e.g., a temperature, a pH, an osmolality, astrain, a stress, a pressure, a state of binding with a ligand, aconformational state) of one or more regions or elements of a target.For example, a center frequency or amplitude of an emission peak of afluorophore could be related to a binding state of a protein thatincludes the fluorophore (e.g., due to quenching of the fluorophore byanother aspect of the protein due to a change in conformation of theprotein related to binding of the protein to a ligand). In anotherexample, a center frequency or amplitude of an emission peak of afluorophore could be related to a presence of calcium in the targetproximate to the fluorophore (e.g., the fluorophore could include one offura-2, indo-1, fluo-3, calcium green-1, or some other fluorescentcalcium indicator). In such examples, the spectral resolution could bespecified such that the related property can be determined and/ordetermined to a specified resolution by detecting the relatedspectrographic property. In some examples, such fluorophores could bealready present in the target.

An SLM (e.g., 110) as described herein and used to provide hyperspectralimaging and/or the determination of spectrographic data for one or moreregions of a target (e.g., 105) has one or more chromatically dispersiveproperties that are electronically (or otherwise) controllable and thatallow the SLM to spectrally disperse light presented to the SLM. Achromatically dispersive property of an object or material is an opticalproperty that has a dependence on the wavelength of light interactingwith the object or material. For example, certain glasses havechromatically dispersive refractive indexes in that the refractiveindexes of the glasses are different for different wavelengths of light.In another example, certain diffraction gratings have differenteffective absorbances and/or angles of reflection for differentwavelengths of light. Thus, such objects or materials havingchromatically dispersive properties can be used to spectrally disperselight, i.e., to interact with light applied to the object or material ina wavelength-dependent manner such that light emitted from the object ormaterial (e.g., reflected from, absorbed by, transmitted through,optically rotated by) has one or more properties (e.g., an angle, anamplitude, an orientation of polarization) that are wavelength-dependentthat were substantially not wavelength-dependent in the applied light.As an example, a prism (e.g., a triangular prism) composed of a glasshaving a chromatically dispersive refractive index could interact with abeam of white light (e.g., a beam containing light at a variety ofamplitudes across the visible spectrum) such that light emitted from theprism at a various visible wavelengths is emitted at respectivedifferent angles (e.g., as a ‘rainbow’).

Such chromatically dispersive objects or materials could be applied todetect spectrographic information about light (e.g., light received froma target) by separating, selectively transmitting, or otherwiseinteracting with light at different wavelengths, allowing the amplitudeor other properties of such light at different wavelengths to beindependently detected (e.g., by a plurality of respectivelight-sensitive elements of a camera, spectrometer, or other sensingdevice) and used to determine spectrographic information (e.g., a vectorof values representing the amplitude at a variety of respectivedifferent wavelengths, a center frequency, width at half maximum,amplitude, shape, or other properties of a peak or other feature) aboutthe light. Further, electronic control of such chromatically dispersiveproperties could allow control of one or more properties of thedispersed light, e.g., a mean angle and/or direction of the dispersedlight, a degree of angular or other separation of different wavelengthsof light (related, e.g., to a spectral resolution of an imager includingsuch electronically controlled dispersive element(s)), a linearity ornonlinearity of the separation of different wavelengths of light, orsome other properties of the dispersed light.

An example of such an electronically-controlled chromatically dispersiveelement is illustrated in cross-section in FIG. 2A. FIG. 2A illustratesthe configuration of a spatial light modulator (SLM) 200 that includes areflective layer 220 (composed of, e.g., aluminum, silver, or some othermaterial that is reflective to light within a range of wavelengths ofinterest) disposed beneath a refractive layer 210. A substantiallytransparent first electrode 240 (composed, e.g., of indium-tin-oxide(ITO) or some other material that is electrically conductive andsubstantially transparent to light within a range of wavelengths ofinterest) is located on the refractive layer 210 opposite from thereflective layer 220. Light directed toward the SLM 200 could betransmitted through the first electrode 240, refracted by the refractivelayer 210, reflected by the reflective layer 220, refracted again by therefractive layer 210, and transmitted away from the SLM 200 through thefirst electrode 240. The SLM 200 additionally includes a dielectriclayer 250 and a plurality of further electrodes 230 (including second235 a, third 235 b, and fourth 235 c electrodes) disposed beneath thereflective layer 220. A controller 260 is configured to control voltagesbetween the first electrode 240 and each of the further electrodes 230.Note that the reflective layer 220 and dielectric layer 250 areillustrated as distinct structures of the SLM 200, but in practice couldbe the same structure (e.g., the dielectric layer 250 could be composedof a reflective material such that the reflective layer 220 is simplythe surface of the dielectric layer 250, the reflective layer 220 couldcomprise a polished or otherwise formed or treated surface of thedielectric layer 250 such that the reflective layer 220 is reflective).

The refractive layer 210 is composed of a material (e.g., a liquidcrystal) that is chromatically dispersive with respect to its refractiveindex. That is, the refractive index of the refractive layer 210 dependson the wavelength of light refracted by the refractive layer 210. Insome examples, the refractive index of the refractive layer 210 couldvary substantially linearly with wavelength for wavelengths within aspecified range of wavelengths (e.g., visible wavelengths, a range ofwavelengths including emission wavelengths of two or more fluorophores).Further, the refractive index of the refractive layer 210 can becontrolled electronically by applying a controlled electric field to therefractive layer 210, e.g., by applying a voltage between the firstelectrode 240 and one or more of the further electrodes 230. Therefractive index of the refractive layer 210 could be related to alinear or nonlinear function of a DC voltage, an amplitude, frequency,duty cycle, pulse width, or other property of an AC voltage, or someother property of voltage applied between the first electrode 240 andone or more of the further electrodes 230. Further, the refractive indexof individual regions or cells of the refractive layer 210 could becontrolled independently or semi-independently by applying differentvoltages, voltage waveforms, or other different electronic signalsbetween the first electrode 240 and one or more of the furtherelectrodes 230 corresponding to the individual regions or cells of therefractive layer 210. For example, the refractive index of first 215 a,second 215 b, and third 215 c cells of the refractive layer 210 could becontrolled by controlling a voltage or voltage waveform applied betweenthe first electrode 240 and the first 235 a, second 235 b, and third 235c further electrodes, respectively.

Note that the SLM 200 is illustrated in cross-section in FIG. 2A andthus shows only a single row of cells (e.g., 215 a-c) and correspondingelectrodes (e.g., 235 a-c) of the SLM 200. The SLM 200 could include aregular, two-dimensional array of such cells. Such an array couldinclude a rectangular, square, hexagonal, or other repeating ornon-repeating array of such cells and electrodes. Alternatively, an SLMcould be configured to have electrodes and corresponding cells or otherregions of a refractive layer according to some other pattern orapplication, e.g., a repeating pattern of linear electrodes (e.g., a1-dimensional array of cells across the surface of the SLM). Thevoltages, voltage waveforms, or other electronic signals applied to theelectrodes could be controlled such that the refractive index of therefractive layer varies across the surface of the SLM according to aspecified pattern, e.g., according to a locally or globallysubstantially linear or nonlinear gradient. Such a local or globalgradient could have a specified magnitude, a specified direction, orsome other specified properties. Further, such specified patterns (e.g.,gradients) could be changed over time according to some application. Forexample, light could be received from a target, reflected from such anSLM, and imaged by a camera or other imaging element to allow imagecapture of light received from a target during a plurality of periods oftime when operating the SLM according to respective different patterns(e.g., gradients having respective specified magnitudes and directions)to spectrally disperse the imaged light in a plurality of respectiveways, allowing determination of spectrographic information for regionsof the target based on the plurality of images, e.g., via a process ofdeconvolution.

FIG. 2B illustrates a variety of functions describing the dependence ofthe refractive index of portions of the refractive layer 210 (thevertical axis, ‘RI’) on the wavelength of refracted light (thehorizontal axis, ‘WAVELENGTH’) when composed of different materialsand/or when exposed to different electrical fields (e.g., when aspecified voltage or voltage waveform is applied between the firstelectrode 240 and one of further electrodes 230 corresponding to a cellof the SLM 200). ‘B’, ‘G’, and ‘R’ indicate the wavelengths of blue,green, and red light, respectively.

Functions X, Y, and Z illustrate the wavelength-dependent refractiveindex of a first refractive layer material composition. The firstrefractive layer material composition has a refractive index that variessubstantially linearly across the illustrated range of wavelengths.Functions X, Y, and Z illustrate the refractive index of a cell of thefirst refractive layer material composition as an applied electronicsignal is varied (e.g., X, Y, and Z are the refractive index of the cellas a voltage between electrodes opposite the cell is increased). X, Y,and Z show increasing overall refractive index as well as a decreasingslope of dependence between the refractive index and wavelength.Similarly, functions V and W illustrate the wavelength-dependentrefractive index of a second refractive layer material composition; Vand W illustrate the refractive index of a cell of the second refractivelayer material composition as an applied electronic signal is varied.

Note that the illustrated functions are intended to illustrateconfigurations and operations of embodiments described herein, and notto limit the embodiments described herein or to describe any particularrefractive layer material composition or dependence of opticalproperties thereof on electronic signals. A refractive index at one ormore wavelengths, a slope and/or offset of the refractive index across arange of wavelengths, a nonlinearity of the relationship between therefractive index and wavelength, or some other property of therefractive index of material included in a refractive layer of an SLM asdescribed herein could change linearly or nonlinearly with one or moreproperties of an applied electrical signal (e.g., an electric fieldmagnitude, an electric field direction, an applied current magnitude, anapplied current direction, a frequency, duty cycle, pulse width, orother property of an applied electrical signal).

FIG. 2C illustrates the use of an SLM 201 configured similarly to SLM200 and having a refractive layer composed of the first materialcomposition. The SLM 201 is operated such that the refractive layer hasa substantially linear gradient of refractive index between thelocations indicated by ‘X’ and ‘Y’ and such that the locations indicatedby ‘X’ and ‘Y’ have wavelength-dependent refractive indexescorresponding to the functions ‘X’ and ‘Y’, respectively (e.g., bycontrolling electrodes of cells proximate to ‘X’ and ‘Y’ according tocorresponding voltages or voltage waveforms and controlling one or morecells located between ‘X’ and ‘Y’ according to some intermediatevoltages). An incoming light 280 c includes light at wavelengthscorresponding to the ‘R’, ‘G’, and ‘B’ indications in FIG. 2B. Theincoming light 280 c is reflected and refracted by the SLM 201 andemitted as reflected light 290 c. Due to the wavelength-dependence ofthe refractive index of the refractive layer of the SLM 201, reflectedlight 290 c is spectrally dispersed (illustrated as separate ‘R’, ‘G’,and ‘B’ rays of light). The angle of each ray of the reflected light 290c could be related to the thickness of the refractive layer of the SLM201 and the pattern of change of the refractive index of the refractivelayer for each ray across the refractive layer. For example, the angleof the ‘B’ ray could be related to a magnitude and/or angle of agradient of the refractive index of the refractive layer for light atwavelength ‘B’ across the SLM 201 in the area proximate the intersectionof the SLM 201 and the incoming light 280 c.

An amount of spectral dispersion of light reflected by an SLM could beincreased by increasing a magnitude of a gradient or other rate ofchange in a pattern of the refractive index of the refractive layer.Such an increase in spectral dispersion could allow spectrographicinformation for a received light to be determined to with a higherspectral resolution, e.g., by causing light of two different wavelengthsto be detected by light-sensitive elements (e.g., pixels) of a camerathat are farther apart by increasing an angle between rays of dispersedlight at the two different wavelengths. As an example, FIG. 2Dillustrates the use of the SLM 201 shown in FIG. 2C. The SLM 201 isoperated such that the refractive layer has a substantially lineargradient of refractive index between the locations indicated by ‘X’ and‘Z’ and such that the locations indicated by ‘X’ and ‘Z’ havewavelength-dependent refractive indexes corresponding to the functions‘X’ and ‘Z’, respectively (e.g., by controlling electrodes of cellsproximate to ‘X’ and ‘Z’ according to corresponding voltages or voltagewaveforms and controlling one or more cells located between ‘X’ and ‘Z’according to some intermediate voltages). An incoming light 280 dincludes light at wavelengths corresponding to the ‘R’, ‘G’, and ‘B’indications in FIG. 2B. The incoming light 280 d is reflected andrefracted by the SLM 201 and emitted as reflected light 290 d. Due tothe wavelength-dependence of the refractive index of the refractivelayer of the SLM 201, reflected light 290 d is spectrally dispersed.Further, the degree of dispersion of the reflected light 290 d (e.g.,the angular separation between the rays ‘R’, ‘G’, and ‘B’) is increasedrelative to that shown in FIG. 2C. This could be due to the increaseddifference in the magnitude of the pattern of change of the refractiveindex of the refractive layer for each ray across the refractive layerrelative to that of the SLM 201 when operated as illustrated in FIG. 2C.For example, the difference in refractive index between points ‘X’ and‘Z’ of FIG. 2D is increased more relative to difference in refractiveindex between points ‘X’ and ‘Y’ of FIG. 2C the for light of shorterwavelengths (e.g., for light at wavelength ‘B’) than for light of longerwavelengths (e.g., for light at wavelength ‘R’).

An amount of spectral dispersion of light reflected by an SLM could belinear (e.g., a degree of angular separation between spectrallydispersed light at 300 nm and 350 nm could be substantially equal to adegree of angular separation between spectrally dispersed light at 350nm and 400 nm), nonlinear (e.g., a degree of angular separation betweenspectrally dispersed light at 300 nm and 350 nm could be greater than adegree of angular separation between spectrally dispersed light at 350nm and 400 nm), or according to some other relationship related to thecomposition of refractive and/or reflective elements of the SLM andelectrical signal applied to such elements (e.g., to a pattern ofvoltage applied to cells of such an SLM). As an example, FIG. 2eillustrates the use of an SLM 202 configured similarly to SLM 200 andhaving a refractive layer composed of the second material composition.The SLM 202 is operated such that the refractive layer has asubstantially linear gradient of refractive index between the locationsindicated by ‘V’ and ‘W’ and such that the locations indicated by ‘V’and ‘W’ have wavelength-dependent refractive indexes corresponding tothe functions ‘V’ and ‘W’, respectively (e.g., by controlling electrodesof cells proximate to ‘V’ and ‘W’ according to corresponding voltages orvoltage waveforms and controlling one or more cells located between ‘V’and ‘W’ according to some intermediate voltages). An incoming light 280e includes light at wavelengths corresponding to the ‘R’, ‘G’, and ‘B’indications in FIG. 2B. The incoming light 280 e is reflected andrefracted by the SLM 202 and emitted as reflected light 290 e. Due tothe wavelength-dependence of the refractive index of the refractivelayer of the SLM 202, reflected light 290 e is spectrally dispersed.Further, the degree of dispersion of the reflected light 290 e is notuniform across waveforms. For example, a degree of angular separationbetween the rays ‘R’ and ‘G’ is less than the degree of angularseparation between the rays ‘G’ and ‘B’. This could be due to theincreased magnitude of change of the refractive index of the refractivelayer for each ray owing to the nonlinearity of the functions ‘V’ and‘W’.

Received light that has been spectrally dispersed by an SLM as describedherein (e.g., 280 a, 280 b, 280 c dispersed into 290 c, 290 d, 290 e,respectively) could be applied to an array of light-sensitive elements(e.g., of a camera, as 130) to allow detection of spectrographicinformation of the received light. In such an example, light of thedispersed light that is at different wavelengths will intersectdifferent light-sensitive elements, such that each light-sensitiveelement with have an output altered (e.g., increased) by the presence oflight at a corresponding wavelength in the received light. In exampleswherein the received light comprises a beam that is received from aparticular region of a target, a 1-dimensional array of suchlight-sensitive elements could be used to detect spectrographicinformation for the particular region by detecting amplitudes (or otherproperties) of the received light that has been spectrally dispersed bythe SLM.

Alternatively, a 2-dimensional array of light sensitive elements couldbe used. In such examples wherein light is received from a plurality ofregions of a target (e.g., as in bright-field microscopy) eachlight-sensitive element of such a 2-dimensional array could receivelight of a variety of different wavelengths from a variety of respectivedifferent regions of the target. A correspondence between individuallight-sensitive element of such an array to light of a range of regionsof a target at a range of corresponding wavelengths could be determined(e.g., by modeling or simulation of elements of such an imaging system,by empirical testing of such a system using one or more calibrationtargets having respective known patterns of spectrographic properties)and such a correspondence could be used to determine spectrographicinformation for one or more regions of an imaged target based on anumber of images of the target taken while operating the SLM accordingor a respective number of different patterns of refractive index (e.g.,via a process of deconvolution). Such multiple patterns of refractiveindex across the SLM could include gradients having multiple respectivespecified magnitudes, directions, or other properties.

FIG. 3A illustrates a target 300 a. Spectrographic properties of regionsof the target 300 a are such that red region Ra contains fluorophoresthat emit red light in response to illumination, green region Gacontains fluorophores that emit green light in response to illumination,and blue region Ba contains fluorophores that emit blue light inresponse to illumination. The target 300 a could be imaged by an imagingsystem as described herein, e.g., by system 100 operated such that allof the mirrors (e.g., 151, 153) of the MD 150 are controlled to reflectfirst illumination 121 toward the target 300 a (such that, e.g., thewhole area of the target 300 a is illuminated) and to reflect lightresponsively emitted from the target 300 a, via reflection from the SLM110, toward the camera 130 such that the light-sensitive elements of thecamera 130 can be operated to image the light received from the target300 a and spectrally dispersed by the SLM 110.

FIG. 3B illustrates a portion of a first image 300 b of the target 300a. This first image 300 b is taken of light received from the targetthat has been spectrally dispersed by an SLM (e.g., 110, 200, 201, 202)during a first period of time. The first image 300 b includesilluminated regions Rb, Gb, and Bb due to illumination of correspondingregions of a camera by dispersed light from the red, green, and blueregions (Ra, Ga, and Ba), respectively, of the target 300 a. The SLM isoperated during the first period of time such that its refractive layerhas a refractive index that varies spatially across the SLM according toa gradient in a first direction (indicated by the arrow 310 b) such thatlight of different wavelengths is dispersed in the first direction 310 bwhen imaged by a camera (e.g., as in the first image 300 b). Suchdispersion affects imaging of the dispersed light during the firstperiod of time by shifting light at longer wavelengths farther in thedirection of the arrow within the first image 300 b; as a result, thefirst image 300 b of the target 300 a includes illuminated regions Rb,Gb, and Bb arranged as shown.

An imaging system (e.g., 100) could be operated in this way during aplurality of further periods of time to generate a further plurality ofrespective images of light received from the target and dispersed by theSLM. The SLM could be operated during such further periods of time tosuch that its refractive layer has a refractive index that variesspatially across the SLM according to respective gradients in respectivefurther directions and/or having respective further magnitudes oraccording to some other set or respective patterns. FIGS. 3C and 3Dillustrate portions of a second image 300 c and a third image 300 d,respectively, of the target 300 a. The second image 300 c and thirdimage 300 d are taken of light received from the target that has beenspectrally dispersed by the SLM during respective second and thirdperiods of time. The second image 300 c and third image 300 d includerespective sets of illuminated regions Rc, Gc, and Bc and Rd, Gd, and Bddue to illumination of corresponding regions of the camera by dispersedlight from the red, green, and blue regions (Ra, Ga, and Ba),respectively, of the target 300 a.

The SLM is operated during the second and third periods of time suchthat its refractive layer has a refractive index that varies spatiallyacross the SLM according to a gradient in a second direction and a thirddirection, respectively (indicated by the arrows 310 c, 310 d,respectively) such that light of different wavelengths is dispersed inthe second direction 310 c and third direction 310 d when imaged duringthe second and third periods of time by the camera (e.g., as in thesecond 300 c and third 300 d images). Such dispersion affects imaging ofthe dispersed light during the second and third periods of time byshifting light at longer wavelengths farther in the direction ofrespective arrows within the second 300 c and third 300 d images. As aresult, the second image 300 c of the target 300 a includes illuminatedregions Rc, Gc, and Bc and the third image 300 d of the target 300 aincludes illuminated regions Rd, Gd, and Bd arranged as shown. Notethat, in this illustrative example, overlapping regions in the images(e.g., the region of overlap between Gc and Bc in the second image 300c, the region of overlap between Gd and Bd in the third image 300 d)could be represented by an increased measured intensity or otherincreased detected property of the dispersed light due to receivinglight from both the green region Ga and blue region Ba of the target 300a

Such multiple images of the target 300 a, taken from light dispersed inrespective multiple ways by the SLM operated according to respectivemultiple configurations of refractive index (e.g., according togradients having respective different directions and/or magnitudes)could be used to determine spectrographic information for one or moreregions (e.g., particular region Pa) of the target 300 a. In someexamples, such information could be determined for a plurality ofregions across the target 300 a allowing, e.g., hyperspectral imaging ofthe target 300 a. A plurality of such images, in combination with amodel or other algorithm describing the effects of the plurality ofpatterns of refractive index of the SLM and/or the effects of suchconfigurations to disperse light received from the target 300 a duringthe periods of time corresponding to the plurality of images. Such adetermination could include a process of deconvolution or some othercomputational process.

In an illustrative example, spectrographic information about theparticular region Pa of the target 300 a could be determined based onthe amplitude or other detected information about light detected atregions of the camera (e.g., by one or more light-sensitive elements orpixels of the camera) corresponding, according to the location of theparticular region Pa and the dispersive effects of the SLM during theplurality of periods of time corresponding to the plurality of images.For example, an amplitude of red light emitted from Pa in response toillumination by the imaging system could be determined based on a linearcombination or other function of the light detected at points Prb, Prc,and Prd in the first 300 a, second 300 b, and third 300 c images of thetarget. Similarly, an amplitude of green light emitted from Pa inresponse to illumination by the imaging system could be determined basedon a linear combination or other function of the light detected atpoints Pgb, Pgc, and Pgd in the first 300 a, second 300 b, and third 300c images of the target and an amplitude of blue light emitted from Pa inresponse to illumination by the imaging system could be determined basedon a linear combination or other function of the light detected atpoints Pbb, Pbc, and Pbd in the first 300 a, second 300 b, and third 300c images of the target.

The location of such corresponding locations (e.g., Prb, Prc, Prd, Pgb,Pgc, Pgd, Pbb, Pbc, Pbd) could be determined based on a model of theimager (e.g., based on the magnitude and direction of a gradient ofrefractive index of the refractive layer across the SLM) and/or on anempirical measurement of the properties of the imager (e.g., based on aset of images of a calibration target having known spectrographicinformation/content or some other calibration information or procedure).Note that the colors (red, green, and blue) and operation of the SLM todisperse light in the illustrated different directions are intended asnon-limiting examples; different wavelengths and/or ranges ofwavelengths of spectrographic information could be determined forregions of a target. Further, an SLM could be operated to have a patternof refractive index according to gradients having respective differentdirections, magnitudes, or according to some other set of patterns ofrefractive index.

A spectral and/or spatial resolution of such determined spectrographicinformation could be increased by capturing more images of the target300 a while operating the SLM to have respective different patterns ofrefractive index (e.g., gradients having respective different magnitudesand directions, other patterns). Such patterns could includesubstantially linear gradients across the entire refractive layer of theSLM, patterns having a variety of local gradients (themselves havingrespective magnitudes and/or directions) in refractive index, or someother random or pseudo-random patterns of refractive index according toan application. Additionally or alternatively, a magnitude of a gradientin such a pattern or refractive index of an SLM could be increased toincrease a spectral resolution of such determined spectrographicinformation. Further, such a gradient magnitude could be adaptivelyadjusted, e.g., to allow two or more peaks (e.g., corresponding torespective two or more fluorophores in a target) in an emission or otherspectrum of received light to be distinguished.

Note that the described regular array of electrodes disposed as part ofan SLM to allow the electronic control of the refractive index ofrespective cells or other specified regions of a refractive layer (orother refractive element(s)) of the SLM is intended as one exampleembodiment of an SLM having a refractive layer having a refractive indexthat can be electronically controlled to vary across the refractivelayer according to a controllable gradient having at least one of aspecified direction or magnitude. Alternative embodiments couldelectronically control one or more lasers or other light sources tooptically control the refractive index of a refractive element of anSLM. Other configurations and operations of an SLM as described hereinare anticipated. Further, an SLM could be operated in a transmissivemode, i.e., could lack a reflective layer. In such examples, a beam oflight (e.g., a beam of light received from an illuminated target) couldbe spectrally dispersed by the SLM by being transmitted through arefractive layer of the SLM that has a pattern of refractive index thatcan be electronically controlled. In some examples, an SLM could act toprovide electronically controlled spectral dispersion of a beam of lightby controlling a pattern of reflective and absorptive elements on asurface and/or within a volume of the SLM to provide a diffractiongrating having one or more properties (e.g., a grating spacing, agrating width, a grating orientation) that can be electronicallycontrolled to control one or more properties of spectrally dispersedlight reflected from and/or transmitted through the SLM in response toreceiving light from a target.

Other methods of configuring and/or operating a light source, camera,SLM, MD, and/or other elements of an imaging system (e.g., to identifyone or more regions of a target, to photobleach or otherwise interactwith the region of the target based on such identification) areanticipated.

III. Example Confocal Operation of an Imaging Apparatus and ExampleMicromirror Device

Imaging devices as described herein (i.e., imaging devices including oneor more spatial light modulator (SLMs) configured and/or operated asdescribed herein to spectrally disperse light received from a target inan electronically controllable manner) could be configured in a varietyof ways to effect imaging of a target through a variety of methods. Suchmethods could include illuminating and/or receiving light from thetarget according to a variety of patterns (e.g., illuminating andreceiving light from a broad area of the target at once as inbright-field microscopy, illuminating and receiving light from a singlepoint or a small set of points at a time as in confocal microscopy orsome other sort of scanning microscopy). Further, light from a singleregion (or set of spatially distinct regions) of the target could bespectrally dispersed by an SLM and the dispersed light imaged, lightfrom a broad region of the target could be dispersed by an SLM and thedispersed light imaged, or light from the target and/or some specifiedregion(s) of the target could be spectrally dispersed and/or imagedaccording to some other method or combination of methods.

In some examples (e.g., the system 100 illustrated in FIG. 1) one ormore specified regions of a target could be illuminated. Similarly,light responsively emitted from such specified regions, or additional oralternative regions of a target, could be collected, focused, orotherwise received, spectrally dispersed, and detected (e.g., bylight-sensitive elements of a camera) to determine spectrographicinformation for the specified regions and/or for the target as a whole(e.g., to generate a hyperspectral image of the target). An imagingsystem could be configured in a variety of ways to illuminate and/or toreceive light from one or more specified regions of a target. Forexample, illumination could be delivered to a specified region of thetarget through an aperture and/or from a point source of light. Animaging system could include an optical system configured to direct suchlight to a specified region of the target such that the aperture and/orpoint source is located at a location that is conjugate (i.e., such thatthe light is delivered in-focus to the specified region, as in FIG. 1)to the location of the specified region. Conversely, light received fromthe specified region of the target could be received, in-focus, via suchan aperture and/or via a different aperture that has a location that isconjugate to the location of the specified region.

The location of one or more specified regions to illuminate and/orreceive light from could be controlled by controlling the location ofthe target relating to one or more elements (e.g., an objective) of animaging system (e.g., by controlling the location of an actuated stageto which a biological sample or other target is mounted). Additionallyor alternatively, the location of an aperture through which illuminationis emitted and/or through which light responsively emitted from a targetcould be received could be controlled (e.g., scanned across a range oflocations corresponding to locations on or within the target). Forexample, one or more apertures could be formed as part of a Nipkow diskor some other image scanning apparatus. In some examples, a pattern ofsuch apertures could be programmed into the configuration of a spatiallight modulator (e.g., a pattern of opacity of cells of atransmissive-mode spatial light modulator, a pattern of controlledangles of micromirrors of a micromirror device as in, e.g., FIG. 1).

In some examples, an imaging system could include a micromirror device(MD) comprising a plurality of micromirrors disposed in a planar array(e.g., on a substantially flat surface of the MD). FIGS. 4A and 4Billustrate, in cross-section, such an MD 400. The MD 400 includes aplurality of micromirrors (e.g., 405 a, 405 b, 405 c) disposed on afocal surface 407 of the MD 400. The MD 150 illustrated in FIG. 1 couldbe an MD similar to the MD 400 of FIGS. 4A and 4B. Each micromirror ofthe MD 400 is actuatable in that each micromirror has an angle that iselectronically controllable. In some examples, this could include theindividual micromirrors being configured to have one of two specifiedangles relative to the focal surface 407 (e.g., a first angle ofpositive 12 degrees relative to the plane of the focal surface 407 and asecond angle of negative 12 degrees relative to the plane of the focalsurface 407). Elements of an optical system (not shown, e.g., anobjective, a relay lens system) could be configured to reflect and/orrefract light from the MD 400 to a target (not shown) such that lightemitted from the focal surface 407 (e.g., first illumination 415 emittedby a light source 410 and reflected from a particular mirror, e.g., 405b) is transmitted, in-focus, to corresponding locations on a focalsurface on or within the target (e.g., a particular region within thetarget corresponding to the location of the particular mirror, e.g., 405b, on the focal surface 407).

FIG. 4A illustrates the operation of the MD 400 during a first period oftime to actuate all of the micromirrors of the MD 400 to reflect firstillumination 415 emitted from the light source 410 toward a target (notshown) as bright field illumination 425 a. FIG. 4B illustrates theoperation of the MD 400 during a second period of time to actuate aparticular mirror 405 b of the MD to have a first angle and to reflectfirst illumination 415 emitted from the light source 410 toward aparticular region of the target (not shown) corresponding to thelocation of the particular mirror 405 b on the focal surface 407 asconfocal illumination 425. The remainder of the micromirrors of the MD400 (e.g., 405 a, 405 b) are actuated to have a second angle and toreflect first illumination 415 emitted from the light source 410 aswaste illumination 427 b in a direction that is not toward the target(e.g., toward an optical sink or other heat sink element of an imagerconfigured to dissipate the energy of the waste illumination 427 b). Theparticular mirror 405 b, actuated to the first angle, could also reflectconjugate light 435 b from the particular region of the target toward anSLM, camera, or other elements of an imager (e.g., via an optical systemconfigured to present such light, in-focus, to light-sensitive elementsdisposed on a focal plane of a camera). Other mirrors of the MD 400(e.g., 405 a, 405 c), actuated to the second angle, could reflectnon-conjugate light 437 b from the target (e.g., from the particularregion of the target, from other regions of the target illumination bythe confocal illumination 425, from regions of the target illuminated byillumination scattered from such illumination portions of the target)toward an SLM, camera, or other elements of an imager (e.g., via anoptical system configured to present such light, in-focus, tolight-sensitive elements disposed on a focal plane of a camera).

Generally, an optical system of an imager (e.g., 100, an imagerincluding one or more instances of an SLM, e.g., 110, 200, and/or an MD,e.g., 150, 400) that is configured to image a target and to determinespectrographic information for one or more regions of the target (e.g.,to hyperspectrally image the target) could deliver light (e.g.,illumination, image light) between elements of the imager (e.g.,cameras, MDs, SLMs, apertures) and/or to and from a target in-focus.That is, such an optical system could define a number of focal surfacesof elements of the imager (e.g., a focal surface of an MD on whichmicromirrors of the MD are disposed, a focal surface of a camera onwhich light-sensitive elements (e.g., pixels) of the camera aredisposed) that are conjugate to each other and/or to a focal surface onor within a target of the imaging system (e.g., as illustrated in FIG.1). Related to such a configuration, locations on a particular focalsurface (e.g., a particular region on a focal surface on or within atarget) could correspond to locations on any focal surfaces conjugate tothe particular focal surface (e.g., particular locations and/ormicromirrors of an MD, particular locations and/or light-sensitiveelements of a camera). The optical system could deliver light emittedfrom such locations in-focus to corresponding locations on the conjugatefocal surface(s).

As an illustrative example, FIG. 5A shows a configuration of an MD 500comprising a square array of actuatable micromirrors wherein a singleparticular mirror 510 a is operated to have a first angle and theremainder of the micromirrors are operated to have a second angle. Themicromirrors of the MD are disposed on a focal surface of the MD andincluded in an imaging system that includes an optical system asdescribed elsewhere herein. The optical system is configured to deliverilluminating light in-focus from micromirrors of the MD that areoperated to have the first angle to corresponding locations on a focalsurface on or within a target (i.e., locations on the focal surface onor within the target that correspond to the locations of themicromirrors on the focal surface of the MD). The optical system isfurther configured to direct light emitted from locations on the focalsurface on or within the target in-focus to the focal surface of the MD,and further to direct light reflected from the MD by micromirrorsactuated to the first angle in-focus to a focal plane of a camera (e.g.,a focal plane on which a plurality of light-sensitive elements of thecamera are disposed).

FIG. 5B illustrates the plurality of light-sensitive elements of such acamera 550 b, including a particular light-sensitive element 510 blocated at a location on the focal surface of the camera correspondingto the location of the particular mirror 510 a on the focal surface ofthe MD 500. As illustrated in FIG. 5B, light directed, by the opticalsystem, from the MD 500 to the camera 550 is not reflected, refracted,or otherwise affected by an SLM or other chromatically dispersiveelements as described herein, or is exposed to such an element that isbeing operated in a substantially non-dispersive mode (e.g., arefractive layer of such an SLM is being operated to have asubstantially constant refractive index across the SLM). Such light,emitted from a particular region of the target located at a location onthe focal surface on or within the target, reflected from the particularmirror 510 a, and directed in-focus to the camera 500 b, is illustratedas a spot of illumination 560 b having a location corresponding to thelocation of the particular light-sensitive element 510 b. The amplitudeor other properties of the spot of illumination 560 b could be detectedby the particular light-sensitive element 510 b and/or neighboringlight-sensitive elements of the camera 550 to, e.g., determine anoverall absorbance, emittance, reflectance, or other optical property ofand/or otherwise image the particular region of the target.

Note that the presence of a single light-sensitive element 510 b of thecamera 550 in FIGS. 5B-E corresponding to a single mirror 510 a of theMD 500 in FIG. 5A is meant as an illustrative example. A camera andcorresponding MD of an imaging system could have the same resolution oflight-sensitive elements and micromirrors, respectively (as shown inFIGS. 5A-E), or could have different resolutions. For example, a cameracould include a plurality of light-sensitive elements disposed at alocation on a focal surface of the camera corresponding to a singlemicromirror disposed at a corresponding location on a focal surface ofthe MD; that is, the camera could have a higher resolution that the MD.Other configurations of MDs, camera, optical systems, and other elementsof an imager and other correspondences between light-sensitiveelement(s) of cameras, mirror(s) of micromirror devices, regions on afocal surface on or within a target, and other elements of an imager areanticipated. In some examples, a correspondence between light-sensitiveelements of a camera, micromirrors of an MD, and/or regions of a targetcould be described by a model and/or calibration data (e.g., one or morepoint-spread functions) that could be determined by imaging acalibration target (e.g., a target having known specified spectrographicproperties and/or spatial patterns thereof) or by some other method.

FIG. 5C illustrates the plurality of light-sensitive elements of thecamera 550 when light is directed, by the optical system, from the MD500 to the camera 550 by being reflected, refracted, or otherwiseaffected by an SLM or other chromatically dispersive element (e.g., aprism or diffraction grating) to spectrally disperse the reflectedlight. Such light, emitted from a particular region of the targetlocated at a location on the focal surface on or within the target,reflected from the particular mirror 510 a, and directed in-focus to thecamera 500, is illustrated as a band of spectrally disperse illumination560 c (the wavelength of light within the spectrally disperseillumination 560 c being indicated by the ‘R’, ‘G’, and ‘B’ indicatingred, green, and blue light, respectively) having a locationcorresponding to the location of the particular light-sensitive element510 b. The amplitude or other properties of the band of illumination 560c at various points within the band of illumination 560 c (e.g.,corresponding to second 509 b and third 511 b light-sensitive elements)could be detected by the particular light-sensitive element 510 b and/orneighboring light-sensitive elements, e.g., 509 b, 511 b, of the camera550 to, e.g., determine an absorbance, emittance, reflectance, or otheroptical property of the particular region of the target at respectivecorresponding wavelengths and/or ranges of wavelengths. For example, adegree of emission of green, red, and blue light by the particularregion of the target in response to illumination could be detected bydetecting an intensity of light received by the particularlight-sensitive element 510 b, the second light-sensitive element 509 b,and the third light-sensitive element 511 b, respectively.

A spectral resolution of such a system could be increased by increasingan amount of spectral dispersion of the light received by the camera 550(e.g., by increasing a magnitude of a controlled gradient in therefractive index of a refractive layer or other element of an SLMoperated and/or configured to spectrally disperse the light). FIG. 5Dillustrates the plurality of light-sensitive elements of the camera 550when light is directed, by the optical system, from the MD 500 to thecamera 550 by being reflected, refracted, or otherwise affected by anSLM or other chromatically dispersive element(s) as described herein tospectrally disperse the reflected light to a greater degree than thedegree of spectral dispersion illustrated in FIG. 5C. As a result, theband of spectrally disperse illumination 560 d (the wavelength of lightwithin the spectrally disperse illumination 560 d being indicated by the‘R’, ‘G’, and ‘B’ indicating red, green, and blue light, respectively)is longer and illuminates more light-sensitive elements of the camera550. The amplitude or other properties of the band of illumination 560 dat various points within the band of illumination 560 d (e.g.,corresponding to second 509 b, third 511 b, fourth 508 b, and fifth 512b light-sensitive elements) could be detected by the particularlight-sensitive element 510 b and/or neighboring light-sensitiveelements, e.g., 508 b, 509 b, 511 b, 512 b, of the camera 550 to, e.g.,determine an absorbance, emittance, reflectance, or other opticalproperty of the particular region of the target at respectivecorresponding wavelengths and/or ranges of wavelengths. Due to theincreased spectral dispersion of the band of spectrally disperseillumination 560 d relative to that illustrated in FIG. 5C, individuallight-sensitive elements receive light from a narrower band ofwavelengths relative to the scenario illustrated in FIG. 5C, resultingin a higher spectral resolution of spectrographic information determinedfrom the operation of the camera.

Note that the spectral dispersion of light directed to light-sensitiveelements of a camera need not be linear (e.g., as illustrated in FIGS.5C and 5D). That is, bands of wavelengths of light received byneighboring light-sensitive elements could have different widths, e.g.,a first light-sensitive element of a camera could receive light from aparticular region of a target that has wavelengths between 550 nm and560 nm while a neighboring light-sensitive element could receive lightfrom the particular region of the target that has wavelengths between560 nm and 590 nm. Such a correspondence between light-sensitiveelements of a camera and corresponding regions of a target and ranges ofwavelengths of light emitted from the target could be related to theoperation of an SLM or other chromatically dispersive element (e.g., toa magnitude and/or gradient of a pattern of refractive index across arefractive later of an SLM). In some examples, a correspondence betweenlight-sensitive elements of a camera and regions of a target and rangesof wavelengths of light emitted from the target could be described by amodel and/or calibration data (e.g., one or more point-spread functions)that could be determined by imaging a calibration target (e.g., a targethaving known specified spectrographic properties and/or spatial patternsthereof) when an SLM is operated according to one or more patterns ofrefractive index or by some other method.

Note further that an overall pattern and/or level of spectral dispersion(e.g., a maximum possible level of change in wavelength of lightreceived from a particular region of a target between adjacentlight-sensitive elements) could depend, in addition to the configurationof an SLM and, e.g., the pattern of refractive index of a refractivelayer of the SLM, on the configuration of the optical system to directlight to the SLM (e.g., from an MD, from a target, from an aperture) andto direct light from the SLM to the camera. For example, in the system100 illustrated in FIG. 1, an amount of dispersion of the dispersedlight 133 (e.g., a separation of light at two different wavelengthsreceived from a particular region of the target 105 when focused on thefoal surface 137 of the camera 130) could be related to a focal lengthof the relay lenses 143, 144. For example, configuring the relay lenses143, 144 to have longer focal lengths could, for a given configurationand/or operation of the SLM 110, increase an amount of spectraldispersion in the dispersed light 133. Further, a level of collimation(e.g., a degree of planarity of the light collimated by the relay lens143) of light presented to an SLM (e.g., 110) or other chromaticallydispersive element could affect a pattern, linearity, uniformity (e.g.,uniformity of degree and/or linearity of dispersion of light receivedfrom different locations of a target, e.g., 105, and/or MD, e.g., 150)or other properties of light spectrally dispersed by such an SLM orother chromatically dispersive element.

FIGS. 5A-5D illustrate the operation of an imaging system including anMD 500 to illuminate and to receive light from (i.e., to image) a singleregion of a target (e.g., a region having a location on a focal surfaceon or within the target corresponding to the location of the singleparticular mirror 510 a that is controlled to have the first angle. Aplurality of such regions could be sequentially imaged (e.g., aplurality of regions corresponding to the plurality of mirrors of the MD500) by sequentially operating individual mirrors to illuminate suchregions and to reflect light from such regions to a camera or otherelements of an imager. However, a set of such mirrors could becontrolled to have the first angle, such that a plurality ofcorresponding regions on the focal surface on or within the target couldbe simultaneously illuminated and/or imaged. The spacing of such regionsand/or mirrors in such a set of mirrors on a focal surface of the MDcould be specified to be greater than some minimum distance related toproperties of the imager according to some application, e.g., tominimize out-of-focus light from illuminated regions of the target frombeing reflected by a mirror of the MD that does not correspond to suchilluminated regions of the target. Additionally or alternatively, someother pattern of operation of mirrors of an MD (e.g., a pseudo-randompattern, a coded aperture, some other specified pattern(s)) could beused to illuminate, receive light from, or otherwise image or interactwith regions of a tissue.

As an illustrative example, FIG. 6A shows a configuration of an MD 600comprising a square array of actuatable micromirrors wherein a first setof particular mirrors 610 a, 615 a, 616 a, 617 a are operated to have afirst angle and the remainder of the micromirrors are operated to have asecond angle. The micromirrors of the MD are disposed on a focal surfaceof the MD and included in an imaging system that includes an opticalsystem as described elsewhere herein. The optical system is configuredto deliver illuminating light in-focus from micromirrors of the MD thatare operated to have the first angle to corresponding locations on afocal surface on or within a target (i.e., locations on the focalsurface on or within the target that correspond to the locations of themicromirrors 610 a, 615 a, 616 a, and 617 a on the focal surface of theMD when such mirrors are actuated to have the first angle). The opticalsystem is further configured to direct light emitted from locations onthe focal surface on or within the target in-focus to the focal surfaceof the MD, and further to direct light reflected from the MD bymicromirrors actuated to the first angle in-focus to a focal plane of acamera (e.g., a focal plane on which a plurality of light-sensitiveelements of the camera are disposed). Further, the optical system isconfigured to direct such received light from the MD 600 to the camera650 by being reflected, refracted, or otherwise affected by an SLM orother chromatically dispersive element(s) as described herein tospectrally disperse the reflected light.

FIG. 6B illustrates the plurality of light-sensitive elements of thecamera 650 when light is directed, by the optical system, fromparticular regions of the target located at a locations on the focalsurface on or within the target, reflected from the particular mirrors610 a, 615 a, 616 a, 617 a, and directed in-focus to the camera 650.Such spectrally dispersed light received by the camera 650 isillustrated as bands of spectrally disperse illumination 660 b, 665 b,666 b, 667 b (the wavelength of light within the spectrally disperseillumination being indicated by the ‘R’, ‘G’, and ‘B’ indicating red,green, and blue light, respectively) having respective locationscorresponding to the locations of respective particular light-sensitiveelements 610 b, 615 b, 616 b, 617 b. The amplitude or other propertiesof the bands of illumination 660 b, 665 b, 666 b, 667 b at variouspoints within the bands of illumination 660 b, 665 b, 666 b, 667 b(e.g., corresponding to fifth 608 b, sixth 609 b, seventh 611 b, andeighth 612 b light-sensitive elements) could be detected by theparticular light-sensitive elements 610 b, 615 b, 616 b, 617 b and/orneighboring light-sensitive elements, e.g., 608 b, 609 b, 611 b, 612 b,of the camera 650 to, e.g., determine an absorbance, emittance,reflectance, or other optical property of the particular regions of thetarget at respective corresponding wavelengths and/or ranges ofwavelengths. For example, a degree of emission of green, red,orange-yellow, indigo, and blue light by the first particular region ofthe target 610 a in response to illumination could be detected bydetecting an intensity of light received by the particularlight-sensitive element 610 b, the fifth light-sensitive element 608 b,the sixth light-sensitive element 609 b, the seventh light-sensitiveelement 611 b, and the eighth light-sensitive element 612 b,respectively.

A speed of acquisition of images of the target by such a system could beincreased by increasing the number of regions of the target that areimaged simultaneously by the imager (e.g., by increasing the number ofmirrors of the MD that are controlled to have the first anglesimultaneously). Correspondingly, a degree of spectral dispersion of thelight received by the camera 650 and/or a spectral resolution ofspectrographic information detected/determined for each of the regionscould be reduced, e.g., to prevent overlap of light received fromdifferent regions of the target as projected onto light-sensitiveelements of the camera 650. As an illustrative example, FIG. 6C shows aconfiguration of the MD 600 wherein a second set of particular mirrors(e.g., 610 a, 613 a, 616 a, 618 a) that are greater in number reduced inspacing across the surface of the MD 600 are operated to have the firstangle and the remainder of the micromirrors are operated to have thesecond angle.

FIG. 6D illustrates the plurality of light-sensitive elements of thecamera 650 when light is directed, by the optical system, from the MD600 (operated as shown in FIG. 6C) to the camera 650 by being reflected,refracted, or otherwise affected by an SLM or other chromaticallydispersive element(s) as described herein to spectrally disperse thereflected light to a lesser degree than the degree of spectraldispersion illustrated in FIG. 6B. As a result, the bands of spectrallydisperse illumination (e.g., 660 d, 663 d, 666 d, 668 d) correspondingto illuminated regions of the target and/or particular mirrors (e.g.,610 a, 613 a, 616 a, 618 a, respectively) of the second set of mirrorsare longer and individually illuminate fewer light-sensitive elements ofthe camera 650. For example, the amplitude or other properties of aparticular band of illumination 660 d at various points within the bandof illumination (e.g., corresponding to sixth 609 b and seventh 611 blight-sensitive elements) could be detected by the particularlight-sensitive element 610 b and/or neighboring light-sensitiveelements, e.g., 609 b, 611 b, of the camera 650 to, e.g., determine anabsorbance, emittance, reflectance, or other optical property of thecorresponding particular region of the target at respectivecorresponding wavelengths and/or ranges of wavelengths. Due to thedecreased spectral dispersion of the band of spectrally disperseillumination 660 d relative to that illustrated in FIG. 6B (i.e., 660b), individual light-sensitive elements receive light from a wider bandof wavelengths relative to the scenario illustrated in FIG. 6B,resulting in a lower spectral resolution of spectrographic informationdetermined from the operation of the camera 650. Note that the examplepatterns of mirror operation shown in FIGS. 6A and 6D could be scannedsequentially across the MD 600 to allow imaging of an entire area of atarget, or according to some other application.

In some examples, mirrors of an MD of an imaging system are actuatableto have one of two discrete angles (or some other discrete, finitenumber of angular or other states) relative to the MD (e.g., relative tothe plane of a focal surface of the MD) such that an illumination lightis reflected toward regions of the target corresponding to a first setof mirrors actuated to have a first angle. Such an imaging system couldbe further configured such that light responsively emitted from thecorresponding regions of the target (i.e., conjugate light) is reflectedin a first direction by mirrors of the first set and such that lightresponsively emitted from the non-corresponding regions (e.g., regionsof the target illuminated by out-of-focus light, regions of the targetilluminated by light scattered from the corresponding regions) of thetarget (i.e., non-conjugate light) is reflected in a second direction bya second set of mirrors actuated to have a second angle. In suchexamples, both the conjugate and the non-conjugate light could be usedto image the target, to determine spectrographic information for regionsof the target, or to determine some other information about the target.

FIG. 7A illustrates in cross-section elements of an example imagingsystem 700 configured to image a target 705. The system 700 includes alight source 720 (e.g., a laser), a first camera 730 (illustrated as aplane of light-sensitive elements located on a focal plane 737 of thefirst camera 730), a second camera 770 (illustrated as a plane oflight-sensitive elements located on a focal plane 777 of the firstcamera 770), a micromirror device (MD) 750, a spatial light modulator(SLM) 710, and an optical system (including an objective 741, first 743,second 744, third 775, and fourth 776 relay lenses, a dichroic mirror745, and an optical sink 725) configured to direct light to and from thetarget 705 and between the elements of the system 700. The system 700additionally includes a stage 760 to which the target 705 is mounted.Note that the MD 750 and first 730 and second 770 cameras comprisetwo-dimensional arrays of micromirrors and light-sensitive elements,respectively. Further, note that the optical system (e.g., 741, 743,744, 745, 775, 776) and SLM 710 are configured to direct light betweenthe target 705, MD 550, and first 730 and second 770 cameras such thatlocations on the focal surfaces 757, 737, 777 of the MD 750 and cameras730, 770 correspond to respective locations on the focal surface 707 inthe target 705.

The system 700 illuminates a specified region 709 on a focal surface 707in the target 705 by emitting a first illumination 721 from the lightsource 720 and reflecting the first illumination 721 from the dichroicmirror 745 toward the MD 750. A selected mirror 751 of the MD 750 thathas a location on a focal surface 757 of the MD 750 corresponding to thespecified region 709 is controlled to have a first angle to reflect thefirst illumination 721 toward the target 705 as confocal illumination722 via the objective 741. Other mirrors 753 of the MD 750 arecontrolled to have a second angle to reflect the remainder of the firstillumination 721 as waste illumination 723 toward the optical sink 725to be absorbed. As illustrated, a single mirror (751) is controlled toilluminate (and to receive light from) a corresponding region 709 of thetarget 705; however, additional mirrors (e.g., selected from othermirrors 753) could be operated simultaneously, sequentially, oraccording to some other scheme to illuminate (and to receive light from)corresponding additional regions of the target 705.

The system 700 receives light (including conjugate light 772) emittedfrom the target 705 (e.g., from the specified region 709) in response toillumination via the objective 741. The conjugate light 772 is directed,in-focus, to a specified region 771 on a focal surface 777 of the secondcamera 770 corresponding to the specified region 709 (e.g., to a regionof the second camera having one or more light-sensitive elements and/orpixels of the second camera 770). Such light is directed to the secondcamera 770 from the MD 750 via relay optics 775, 776 or via some otheroptical element(s).

The system 700 also receives non-conjugate light 732 emitted from thetarget (e.g., from regions of the target illuminated out-of-focus by theconfocal illumination 722, from regions of the target illuminated bylight scattered from such regions and/or scattered from the specifiedregion 709) via the objective 741. The non-conjugate light 732 arrives,in-focus, at the focal surface 757 of the MD 750 and reflected bymirrors of the MD 750 that are controlled to have the second angle(e.g., 753) toward the SLM 710. The first relay lens 743 (and/or someother optical elements of the system 700) collimates the received lightand presents the substantially collimated light to the SLM 710. The SLM700 reflects the non-conjugate light 732 as spectrally dispersed light733 toward the second relay lens 744 that is configured to present thespectrally dispersed light 733 in-focus to a focal surface 737 of thefirst camera 730. The SLM 710 is configured and/or operated such thatthe spectrally dispersed light 733 is spectrally dispersed relative tothe non-conjugate light 732 in a controlled manner such thatspectrographic information of one or more particular regions of thetarget 705 and/or of the non-conjugate light 732 can be detected ordetermined (e.g., based on a plurality of images of the target 705generated by the first camera 730 during respective periods of time whenthe SLM 710 is operated according to a respective plurality of patternsof refractive index, e.g., a plurality of controlled gradients havingrespective different magnitudes and/or directions). In some examples,the spectrally dispersed light 733 is spectrally dispersed in a mannerrelated to an electronically controlled direction, magnitude, and/orsome other property of a spatial gradient in the refractive index of alayer of the SLM 710.

Note that the configuration and/or operation of the system 700 toilluminate and to receive conjugate light from a specified region 709 ona focal surface 707 of the target 705 is intended as a non-limitingexample. Alternatively, a larger and/or differently-shaped region of thetarget (e.g., a line within the target; substantially the entire targetand/or the entire target within a field of view of the imaging system700) could be illuminated by operating the mirrors 751, 753 of the MD750 according to a different set of controlled angles than thoseillustrated. For example, a plurality of spatially separated regionsproximate to the focal surface 707 of the target 705 could beilluminated and imaged simultaneously by controlling a correspondingplurality of spatially separated mirrors of the MD 750 to reflect thefirst illumination 721 toward the plurality of the regions of the target705. The mirrors 751, 753 of the MD 750 could be controlled according tosome other pattern, e.g., to approximate some other coded aperture onthe focal surface 757 of the MD 750. Further, the light source 720 couldemit illumination at a controllable wavelength (e.g., illumination thatis substantially monochromatic, but having a wavelength that can bealtered by operation of the light source) and spectrographic informationcould be determined for regions of the target 705 based on images of thetarget 705 generated when the target 705 is illuminated by differentwavelengths of light (e.g., to generate a corresponding plurality ofemission spectra for the region corresponding to the differentwavelengths of illumination).

The system 700 could be operated in a variety of ways to provideconfocal, hyperspectral, or other types of images of the target 705. Forexample, the system could be operated during a number of specifiedperiods of time to illuminate regions of the target (e.g., bycontrolling respective specified sets of mirrors of the DM to have firstor second angles), to electronically control a gradient of refractiveindex across a refractive layer of the SLM to have respective differentspecified magnitude(s) or direction(s) or to control the refractiveindex of element(s) of the SLM according to some other patterns, toimage conjugate or non-conjugate light received from the target 705using the second 770 and first 730 cameras, respectively, or to operatesome other element(s) of the system 700 over time according to anapplication.

FIG. 7B is a timing diagram illustrating an example operation of thesystem 700 to generate monochromatic confocal images of the target 705using the second camera 770 and to generate bright-field hyperspectralimages of the target 705 using the first camera 730. Each horizontaltrace indicates, by enclosed boxes, the timing of operation of variouselements of the system 700 according to respective differentconfigurations. Each box of the ‘MD’ trace indicates a period of timeduring which the mirrors of the MD 750 are controlled according to aspecified pattern; for example, each box could represent the operationof respective disjoint sets of mirrors of the MD 750 to illuminaterespective different regions of the target 705 in a scanning fashion inorder to illuminate, in turn, all regions of the target 705. Each box ofthe ‘SLM’ trace indicates a period of time during which the MD 710 iselectronically controlled to have a respective pattern of refractiveindex across a refractive layer of the SLM; for example, each box couldrepresent the operation of the SLM 710 to have a controlled gradient ina different direction (e.g., as illustrated in FIGS. 3B-D) to disperselight imaged by the first camera 730 in respective different directions.Each box of the ‘CAMERA 1 EXPOSURE’ and ‘CAMERA 2 EXPOSURE’ tracesindicates a period of time during which the cameras 730, 770 areoperated to generate respective images of light received by the cameras730, 770; these periods of time could represent an exposure time orintegration time of light-sensitive elements of the cameras 730, 770(e.g., of a CCD array of the cameras, of an array of active pixelsensors of the cameras). Further, specified first 701 a, second 701 b,third 701 c, fourth 701 d, fifth 701 e, and sixth 701 f periods of timeare indicated in FIG. 7B and correspond to exposure times for the first730 and second 770 cameras.

When the system 700 is operated as shown, a number of confocal imagesand hyperspectral images of the target 705 could be generated based onimages generated by the first 730 and/or second 770 cameras. If thevarious MD 750 settings used during a particular second camera 770exposure (e.g., the exposure that occurs during the first period of time701 a) are specified to scan across the target (e.g., to sequentiallyilluminate and to receive light from respective regions of the target705 such that, at some point in time during the exposure, all regions ofthe target 705 are illuminated), individual images generated by thesecond camera 770 could be used to generate respective confocal imagesof the target 705 (corresponding to periods of time indicated by the‘CONFOCAL FRAME’ trace of FIG. 7B). This could include scaling ornormalizing an image generated by the second camera 770 (e.g., accordingto calibration data describing the optical properties of the system 700)to generate a corresponding confocal image of the target 705.

When the system 700 is operated in such a manner, sets of multipleimages generated by the first camera 730 (e.g., during the first 701 a,second 701 b, and third 701 c periods of time) could be used to generaterespective hyperspectral images of the target 705 (corresponding toperiods of time indicated by the ‘HYPERSPECTRAL FRAME’ trace of FIG.7B). Such a determination could include processes as described herein(e.g., a process of deconvolution, a process similar to the processdescribed by example in relation to FIGS. 3A-D, some other process(es)).Such processes could be based on a description of correspondencesbetween the location of light-sensitive elements of the first camera andcorresponding locations on or within the target. Such correspondencescould be wavelength-dependent and could be determined based on a modelof the system 700 (e.g., based on the magnitude and direction of agradient of refractive index of the refractive layer across the SLM 710during one or more periods of time, e.g., 701 a, 701 b, 701 c) and/or onan empirical measurement of the properties of the system 700 (e.g.,based on a set of images of a calibration target having knownspectrographic information/content or some other calibration informationor procedure).

Note that the timing diagrams illustrated in FIG. 7B to describe theoperation of elements of the system 700 are intended as a non-limitingexample. Other timings of operation of the system 700 are anticipated.Further, spectrographic information, images, or other information aboutregions of the target 705 could be determined based on a combination ofinformation (e.g., images) generated by the first 730 and second 770cameras. The system 700 could be operated according to a variety ofdifferent operational modes. For example, in a first mode the system 700could be operated only to generate confocal images of the target 705 andthe SLM 710 and first camera 730 could be disabled. The system 700 couldinclude a further light source or be otherwise configured such that theSLM 710 and first camera 730 could be operated, in combination with thefurther light source and MD 750, to image conjugate light received fromthe target 705 (e.g., similar to the configuration of system 100) whilethe second camera 770 could be operated to generate bright-field imagesof the target 705. Other configurations and operations of the system700, or of other systems and embodiments as described herein (e.g., 100,200, 400, 500) are anticipated.

The system 700 could be operated to provide a sequence of hyperspectralimages at a specified temporal, spatial, and/or spectral resolution. Insome examples, this could include reducing a first resolution toincrease a second resolution. For example, a temporal resolution (e.g.,a number of hyperspectral images produced per second) could be increasedby increasing a number of regions of the target 705 simultaneouslyimaged (e.g., by increasing a number of spatially distinct mirrors ofthe MD 750 used to simultaneously illuminate respective spatiallydistinct regions of the target 705) such that the whole target could beimaged using fewer corresponding MD 750 configurations (i.e., patternsof controlled angles of mirrors of the MD 750). Correspondingly, aspectral resolution of the images could be reduced (e.g., by reducing adegree of spectral dispersion of received light caused by the SLM 710)to prevent overlap of light received from different regions of thetarget on light-sensitive elements of the first camera 730 (a similarscenario is described in relation to FIGS. 6A-D). In some examples, suchresolutions (e.g., spatial, temporal, spectral) could be specified by auser. Additionally or alternatively, one or more such resolutions couldbe set automatically by a controller of the system 700 (e.g., tomaximize spatial and/or temporal resolution while maintaining spectralresolution at a minimum level sufficient to distinguish emission peaksof respective different fluorophores in the target 705). Otherconfigurations and operations of systems and methods described hereinare anticipated.

IV. Example Electronics of an Imaging Apparatus

FIG. 8 is a simplified block diagram illustrating the components of animaging system 800, according to an example embodiment. Imaging system800 and/or elements thereof may take the form of or be similar to one ofthe example systems or elements 100, 200, 400, 700 shown in FIGS. 1, 2A,4A-B, and 7A. Imaging system 800 may take a variety of forms, such as awall, table, ceiling, or floor-mounted device. Imaging system 800 maytake the form of a bench-top or table-top device (e.g., a bench-topmicroscope). Imaging system 800 and/or elements thereof could also takethe form of a system, device, or combination of devices that isconfigured to be part of another device, apparatus, or system. Forexample, imaging system 800 or element(s) thereof (e.g., spatial lightmodulator 803) could take the form of a system or element configured tobe mounted to or otherwise disposed as part of some other imaging system(e.g., imaging system 800 and/or the spatial light modulator 803 orother elements thereof could be configured to be part of a confocalmicroscope or other imaging system, e.g., to spectrally disperse one ormore beams or fields of light of the imaging system in anelectronically-controllable manner). Imaging system 800 could take theform of a system configured to contents of an industrial environment(e.g., to image integrated circuits, microelectromechanical devices, orother objects in a clean room), medical environment, scientificenvironment, or some other environment. Imaging system 800 also couldtake other forms.

In particular, FIG. 8 shows an example of an imaging system 800 having alight source 801, a first camera 802, a spatial light modulator (SLM)803, a micromirror device (MD) 806, a second camera 807, an opticalsystem 805, a stage actuator 808, a user interface 820, communicationsystem(s) 830 for transmitting data to a remote system, and controller810. The components of the imaging system 800 may be disposed on orwithin a mount or housing or on some other structure for mounting thesystem to enable stable imaging or other functions relative to a targetof interest, for example, a biological sample mounted to a stage (e.g.,a stage having a location relative to other elements of the imagingsystem 800 that is actuated in at least one dimension by the stageactuator 808). The imaging system 800 could include additionalcomponents, for example, a perfusion pump configured to provide aeratedor otherwise chemically specified perfusate to a cell culture or otherbiological sample comprising a target of the imaging system 800, one ormore electrophysiological or optogenetic stimulators and/or sensors, anintegrated circuit test rig, or some other instrument(s) or othercomponent(s) according to an application.

The light source 801, cameras 802, optical system 805, SLM 803, MD 806,and/or stage actuator 808 could be configured and/or disposed as part ofthe imaging device 800 as described elsewhere for similar elements. Theoptical system 805 is configured to direct light emitted by the lightsource 801 to illuminate one or more regions of a target (e.g., viareflection from one or more mirrors of the MD 806). The optical system805 is further configured to receive light responsively emitted from thetarget and to direct such light and/or components of such light (e.g., aconjugate component of the received light, a non-conjugate component ofthe received light) to one or both of the cameras 801, 807 (e.g., viareflection from one or more mirrors of the MD 806, via reflection from,transmission through, or some other chromatically disperse interactionwith the SLM 803). The optical system 805 is configured to direct suchlight between elements (e.g., 802, 806, 807) of the imaging system 800such that focal surfaces of one or more such elements (e.g., a focalsurface of the camera(s) 801, 807 on which is disposed light-sensitiveelements of the camera(s), a focal surface of the MD 806 on which isdisposed mirrors of the MD 806) are optically conjugate with each otherand/or with a focal surface on or within a target of the imaging system800.

Controller 810 may be provided as a computing device that includes oneor more processors 811. The one or more processors 811 can be configuredto execute computer-readable program instructions 814 that are stored ina computer readable data storage 812 and that are executable to providethe functionality of an imaging system 800 as described herein.

The computer readable data storage 812 may include or take the form ofone or more non-transitory, computer-readable storage media that can beread or accessed by at least one processor 811. The one or morecomputer-readable storage media can include volatile and/or non-volatilestorage components, such as optical, magnetic, organic or other memoryor disc storage, which can be integrated in whole or in part with atleast one of the one or more processors 811. In some embodiments, thecomputer readable data storage 812 can be implemented using a singlephysical device (e.g., one optical, magnetic, organic or other memory ordisc storage unit), while in other embodiments, the computer readabledata storage 812 can be implemented using two or more physical devices.

The program instructions 814 stored on the computer readable datastorage 812 may include instructions to perform any of the methodsdescribed herein. For instance, in the illustrated embodiment, programinstructions 814 include an illumination and acquisition module 815 andan image generation module 816.

The illumination and acquisition module 815 can include instructions foroperating the light source 801, first camera 802, SLM 803, MD 806,second camera 807, and/or stage actuator 808 to enable any of thefunctions or applications of an imaging system to determine and/ordetect spectrographic information about regions of a target and/or tohyperspectrally image, confocally image, or otherwise image or opticallyinteract with a target as described herein. Generally, instructions inthe illumination and acquisition module 815 describe methods ofoperating the light source 801 and/or MD 806 to illuminate one or moreregions of a target with light at one or more specified wavelengthsduring one or more respective periods of time. Instructions in theillumination and acquisition module 815 further describe methods ofoperating the SLM 803 to spectrally disperse light directed toward theSLM 803 according to one or more specified directions, magnitudes, orother properties of dispersion of light during one or more respectiveperiods of time (e.g., periods of time synchronous with and/oroverlapping periods of time of operation of the MD 806 and/or lightsource 801).

Instructions in the illumination and acquisition module 815 furtherdescribe methods of operating the camera(s) 801, 807 to generate imagesof light received from illuminated regions of a target via the opticalsystem 805, micromirror device 806, and/or SLM 803 during one or moreperiods of time (e.g., periods of time of operation of the MD 806, SLM803, light source 801, or other components of the imaging system 800).In some examples, generating an image using the camera(s) 801, 807 couldinclude reading out information (e.g., values or signals describing ofrelated to the intensity or other property light detected bylight-sensitive elements of the camera(s) 801, 807. In such examples, aparticular light-sensitive element or set of light-sensitive elements ofthe camera could be substantially unable to detect light when being readout. For example, one or both of the camera(s) could be CMOS camerasconfigured to have a global shutter (i.e., to read out an entire frameof image data from the camera at a time) and/or to have a rollingshutter (i.e., to read out a row of image data from the camera at atime). In such embodiments, the illumination and acquisition module 815could describe operations of an MD 806 or other elements to notilluminate regions of a target corresponding to locations (e.g.,light-sensitive elements) of the camera(s) that are not able to detectlight from such regions (e.g., light-sensitive elements that are beingread out). For example, one of the camera(s) 801, 807 could comprise aCMOS camera configured or operated to have a global shutter, and theillumination and acquisition module 815 could describe operation of theimaging system 800 such that substantially no regions of the target areilluminated by the light source 801 when the CMOS camera is being readout. Other operations, functions, and applications of the light source801, first camera 802, SLM 803, MD 806, second camera 807, stageactuator 808, and/or of other components of the imaging system 800 asdescribed herein could be implemented as program instructions in theillumination and detection module 815.

The image generation module 816 can include instructions for generatingone or more images of the target and/or determining some otherinformation about the target (e.g., spectrographic information for oneor more regions of the target, the identity of contents of a region ofthe target based on such determined spectrographic information) based onone or more images generated by the camera(s) 801, 807. For example, theimage generation module 816 can include instructions for generating oneor more images of the target (e.g., monochrome confocal images) byscaling or normalizing an image generated by one or both of the cameras801, 807 (e.g., according to calibration data describing the opticalproperties of the system 800). The image generation module 816 caninclude instructions for generating spectrographic information about oneor more regions of a target (e.g., to generate a hyperspectral image ofthe target) based on one or more images of spectrally dispersed lightreceived from the target. Such a determination could include processesas described herein (e.g., a process of deconvolution, a process similarto the process described by example in relation to FIGS. 3A-D, someother process(es)). Such processes could be based on a description ofcorrespondences between the location of light-sensitive elements of thecamera(s) 801, 807 and corresponding locations on or within the target.Such correspondences could be wavelength-dependent and could bedetermined based on a model of the imaging system 800 (e.g., based onthe magnitude and direction of a gradient of refractive index of arefractive layer across the SLM 803 during one or more periods of timecorresponding to images generated by the camera(s) 801, 807) and/or onan empirical measurement of the properties of the system 800 (e.g.,based on a set of images of a calibration target having knownspectrographic information/content or some other calibration informationor procedure).

Some of the program instructions of the illumination and acquisitionmodule 815 and/or image generation module 816 may, in some examples, bestored in a computer-readable medium and executed by a processor locatedexternal to the imaging system 800. For example, the imaging system 800could be configured to illuminate and to receive light from a target(e.g., a biological sample) and then transmit related data to a remoteserver, which may include a mobile device, a personal computer, thecloud, or any other remote system, for further processing (e.g., for thedetermination of spectrographic information of one or more regions ofthe target, for identifying the region of the target and/or contentsthereof based on the determined spectrographic content, to generate ahyperspectral image or other variety of image of the target).

User interface 820 could include indicators, displays, buttons,touchscreens, head-mounted displays, and/or other elements configured topresent information about the imaging system 800 to a user and/or toallow the user to operate the imaging system 800. Additionally oralternatively, the imaging system 800 could be configured to communicatewith another system (e.g., a cellphone, a tablet, a computer, a remoteserver) and to present elements of a user interface using the remotesystem. The user interface 820 could be disposed proximate to the lightsource 801, first camera 802, SLM 803, MD 806, second camera 807, stageactuator 808, controller 810, or other elements of the imaging system800 or could be disposed away from other elements of the imaging system800 and could further be in wired or wireless communication with theother elements of the imaging system 800. The user interface 820 couldbe configured to allow a user to specify some operation, function, orproperty of operation of the imaging system 800. The user interface 820could be configured to present an image (e.g., a hyperspectral image) oftarget generated by the imaging system 800 or to present some otherinformation to a user. Other configurations and methods of operation ofa user interface 820 are anticipated.

Communication system(s) 830 may also be operated by instructions withinthe program instructions 814, such as instructions for sending and/orreceiving information via a wireless antenna, which may be disposed onor in the imaging system 800. The communication system(s) 830 canoptionally include one or more oscillators, mixers, frequency injectors,etc. to modulate and/or demodulate information on a carrier frequency tobe transmitted and/or received by the antenna. In some examples, theimaging system 800 is configured to indicate an output from thecontroller 810 (e.g., one or more images of a target) by transmitting anelectromagnetic or other wireless signal according to one or morewireless communications standards (e.g., Bluetooth, WiFi, IRdA, ZigBee,WiMAX, LTE). In some examples, the communication system(s) 830 couldinclude one or more wired communications interfaces and the imagingsystem 800 could be configured to indicate an output from the controller810 by operating the one or more wired communications interfacesaccording to one or more wired communications standards (e.g., USB,FireWire, Ethernet, RS-232).

The computer readable data storage 812 may further contain other data orinformation, such as contain calibration data corresponding to aconfiguration of the imaging system 800, a calibration target, or someother information. Calibration, imaging, and/or other data may also begenerated by a remote server and transmitted to the imaging system 800via communication system(s) 830.

V. Example Methods

FIG. 9 is a flowchart of an example method 900 for operating elements ofan imaging system to perform functions and/or applications of theimaging system. The method 900 includes operating a light source toilluminate a target (902). This could include operating a light-emittingelement (e.g., a laser) of the light source to illuminate the targetand/or one or more regions thereof with light at a particular fixedwavelength (e.g., an excitation wavelength of one or more fluorophoresin the target). This (902) could include illuminating one or moreparticular regions located on a focal surface on or within the target,e.g., by operating one or more mirrors of a micromirror device toreflect light from the light source to the one or more particularregions. Illuminating the target (902) could include illuminating thetarget according to some other pattern or method (e.g., according to acoded aperture, a pattern of structured illumination, or according tosome other pattern(s)).

The method 900 additionally includes electronically controlling aspatial light modulator (SLM) during a first period of time such that arefractive index of the SLM has a refractive index that varies accordingto a controllable gradient (904). In some examples, the controlledrefractive index could be a refractive index of a chromatically disperserefractive layer such that light directed toward, reflected from,transmitted through, or otherwise having interacted with the SLM isspectrally dispersed. In some examples, the SLM could further include areflective layer disposed beneath the refractive layer. In someexamples, the SLM could include an array of cells having respectiveelectronically controllable refractive indexes and electronicallycontrolling the SLM (904) could include electronically controlling therefractive indexes of the cells such that the refractive indexes of thecells vary in a direction corresponding to a specified direction of thecontrollable gradient at a spatial rate of change corresponding to aspecified magnitude of the controllable gradient.

The method 900 additionally includes imaging light emitted from thetarget and reflected from the SLM in response to illumination during thefirst period of time to produce a first image of the target (906). Thiscould include an optical system receiving the light emitted from thetarget and directing the received light (e.g., via reflection from oneor more mirrors of a micromirror device) toward the SLM. This (906)could include the optical system collimating such received light beforedirecting the collimated received light toward the SLM. This (906) couldinclude the optical system directing such light in-focus to a focalsurface of a camera or other element(s) configured to image the emittedlight, i.e., the optical system could be configured such that a focalsurface on or within the target is optically conjugate to a focalsurface of a camera (e.g., a surface of the camera on which a pluralityof light-sensitive elements of the camera are disposed). This (906)could include controlling a spectral resolution of spectrographicinformation determined using the method 900 by controlling a magnitudeof the controllable gradient.

The method 900 additionally includes determining spectrographicinformation for a particular region of the target based at least on thefirst image of the target (908). Determining spectrographic informationfor the particular region (908) could include determining the intensityof a beam of light emitted from the particular region at differentwavelengths based on corresponding different pixels of the first imageof the target. In some examples, the method 900 could include imaginglight emitted from the target and reflected from the SLM in response toillumination during a plurality of respective further periods of timewhen the SLM is operated to have respective different refractive indexpatterns (e.g., substantially linear gradients having respectivedirections and/or magnitudes). In such examples, determiningspectrographic information for the particular region (908) could includedetermining such information based on the first image and the pluralityof further images of the target, e.g., by a process of deconvolution.

The method 900 could further include determining calibration informationfor the imaging system. For example, a calibration target having one ormore known patterns of spectrographic properties could be imaged. Acorrespondence between individual light-sensitive elements of a cameraor other element(s) of a system used to image the calibration target andthe location of a range of regions of the calibration target at a rangeof corresponding wavelengths could be determined and such acorrespondence could be used to determine calibration information forthe imaging system. Additionally or alternatively, such calibrationinformation could be based on a model of operation of the imaging system(e.g., a model of the geometric and optical properties of the imagingsystem).

The method 900 could include other additional steps or elements. Themethod 900 could include any additional steps, or could include detailsof implementation of the listed steps 902, 904, 906, 908 or of otheradditional steps, as described herein in relation to the operation of animaging system. Additional and alternative steps of the method 900 areanticipated.

VI. CONCLUSION

The particular arrangements shown in the Figures should not be viewed aslimiting. It should be understood that other embodiments may includemore or less of each element shown in a given Figure. Further, some ofthe illustrated elements may be combined or omitted. Yet further, anexemplary embodiment may include elements that are not illustrated inthe Figures.

Moreover, it is particularly noted that while devices, systems, methods,and other embodiments are described herein by way of example as beingemployed to image biological environments (e.g., tissues extracted froma human body), it is noted that the disclosed devices, systems, andmethods can be applied in other contexts as well. For example, imagingsystems configured as disclosed herein may be included as part of otherscientific and/or industrial imaging apparatus. In some contexts, suchan imaging system could be operated to image an integrated circuit, amicroelectromechanical device, or some other microfabricated device. Inanother example, an imaging system could be configured to image someother device or object. For example, the imaging system could beconfigured and/or applied to image a surface of an electrode, animplant, a bearing, a mineral sample, or some other device or object(e.g., to determine a surface geometry of an object, to determine adisposition of elements or chemical on or within a surface of anobject).

Additionally, while various aspects and embodiments have been disclosedherein, other aspects and embodiments will be apparent to those skilledin the art. The various aspects and embodiments disclosed herein areincluded for purposes of illustration and are not intended to belimiting, with the true scope and spirit being indicated by thefollowing claims. Other embodiments may be utilized, and other changesmay be made, without departing from the spirit or scope of the subjectmatter presented herein. It will be readily understood that the aspectsof the present disclosure, as generally described herein, andillustrated in the figures, can be arranged, substituted, combined,separated, and designed in a wide variety of different configurations,all of which are contemplated herein.

1-20. (canceled)
 21. A system comprising: a light source; a first camera, wherein the first camera comprises a plurality of light-sensitive elements disposed on a focal surface of the first camera; a spatial light modulator, wherein the spatial light modulator comprises a reflective layer disposed beneath a refractive layer, wherein the refractive layer has a refractive index that varies spatially across the spatial light modulator, and wherein the spatial variation of the refractive index is electronically controllable; and an optical system, wherein the optical system optically couples (i) the light source to a target, (ii) the target to the spatial light modulator, and (iii) the spatial light modulator to the first camera.
 22. The system of claim 21, wherein the refractive layer has a refractive index that varies substantially linearly with wavelength for wavelengths within a specified range of wavelengths.
 23. The system of claim 21, wherein the target contains a fluorophore, and wherein the light source emits light at an excitation wavelength of the fluorophore.
 24. The system of claim 21, wherein the optical system optically couples the target to the spatial light modulator and the spatial light modulator to the camera such that the focal surface of the camera is conjugate to a focal surface passing through the target.
 25. The system of claim 21, further comprising: a micromirror device, wherein the micromirror device comprises a substantially planar array of actuatable mirrors disposed on a surface, wherein respective angles of the actuatable mirrors relative to the surface are electronically controllable, wherein the optical system optically couples the light source to the target via reflection from a first set of one or more of the actuatable mirrors, and wherein the optical system optically couples the target to the spatial light modulator via reflection from the first set of one or more actuatable mirrors, and wherein the one or more actuatable mirrors in the first set have a first angle relative to the surface of the micromirror device.
 26. The system of claim 21, further comprising: a second camera, wherein the second camera comprises a plurality of light-sensitive elements disposed on a focal surface of the second camera; a micromirror device, wherein the micromirror device comprises a substantially planar array of actuatable mirrors disposed on a surface, wherein respective angles of the actuatable mirrors relative to the surface are electronically controllable, wherein the optical system optically couples the light source to the target via reflection from a first set of one or more of the actuatable mirrors, wherein the optical system optically couples the target to the second camera via reflection from the first set of one or more actuatable mirrors, and wherein the optical system optically couples the target to the spatial light modulator via reflection from a second set of one or more of the actuatable mirrors, and wherein the one or more actuatable mirrors in the first set have a first angle relative to the surface of the micromirror device and the one or more actuatable mirrors in the second set have a second angle relative to the surface of the micromirror device that is different from the first angle.
 27. The system of claim 21, further comprising an actuated stage, wherein the actuated stage controls the location of the target relative to the optical system.
 28. The system of claim 21, wherein the spatial light modulator comprises an array of cells having respective electronically controllable refractive indexes.
 29. A method comprising: illuminating a target by a light source; electronically controlling a spatial light modulator during a first period of time such that a refractive layer of the spatial light modulator has a refractive index that varies spatially across the spatial light modulator, wherein the spatial light modulator further comprises a reflective layer disposed beneath the refractive layer; receiving, at the spatial modulator, light emitted from the target in response to the light from the light source; reflecting, by the spatial modulator, the light received from the target to a first camera; imaging, by the first camera, the light reflected by the spatial modulator during the first period of time to produce a first image of the target; and determining spectrographic information for a particular region of the target based at least on the first image of the target.
 30. The method of claim 29, further comprising: electronically controlling the spatial light modulator during a plurality of further periods of time such that the refractive index of the refractive layer varies spatially across the spatial light modulator; and imaging light emitted from the target in response to the light from the light source during the plurality of further periods of time using the first camera to produce respective further images of the target, wherein determining spectrographic information for a particular region of the target comprises determining spectrographic information based on the first image and the plurality of further images of the target.
 31. The method of claim 29, further comprising: controlling a spectral resolution of the spectrographic information for the particular region of the target by controlling the spatial variation of the refractive index of the refractive layer across the spatial light modulator.
 32. The method of claim 31, wherein the target contains a fluorophore, wherein a property of an emission spectrum of the fluorophore is related to a property of the target, wherein controlling a spectral resolution of the spectrographic information comprises controlling the spectrographic resolution to be sufficiently high to determine the property of the target based on determined spectrographic information for the particular region of the target.
 33. The method of claim 31, wherein the target contains two fluorophores, wherein the two fluorophores have respective different emission spectra, wherein controlling a spectral resolution of the spectrographic information comprises controlling the spectrographic resolution to be sufficiently high to determine whether the particular region of the target contains the first fluorophore or the second fluorophore based on determined spectrographic information for the particular region of the target.
 34. The method of claim 29, wherein the target contains a fluorophore, and wherein illuminating the target comprises emitting light at an excitation wavelength of the fluorophore.
 35. The method of claim 29, further comprising: operating a micromirror device to electronically control respective angles of actuatable mirrors of the micromirror device relative to a surface during the first period of time, wherein the actuatable mirrors comprise a substantially planar array and are disposed on the surface, and wherein operating the micromirror device to electronically control respective angles of actuatable mirrors of the micromirror device comprises controlling a first set of one or more of the actuatable mirrors to have a first angle relative to the surface of the micromirror device during a specified period of time during the first period of time, and wherein the target is illuminated by the light source via reflection from the first set of one or more actuatable mirrors, and wherein the spatial modulator receives the light emitted from the target in response to the light from the light source via reflection from the first set of one or more actuatable mirrors.
 36. The method of claim 35, wherein operating the micromirror device to electronically control respective angles of actuatable mirrors of the micromirror device relative to a surface comprises controlling the first set of at least one of the actuatable mirrors to have the first angle relative to the surface of the micromirror device during the first period of time, and wherein determining spectrographic information for a particular region of the target based at least on the first image of the target comprises determining spectrographic information for a portion of the target corresponding to the first set of one or more actuatable mirrors based on information in the first image detected by light-sensitive elements of the first camera located proximate to a portion of the focal surface of the first camera corresponding to the portion of the target.
 37. The method of claim 29, further comprising: operating a micromirror device to electronically control respective angles of actuatable mirrors of the micromirror device relative to a surface during the first period of time, wherein the actuatable mirrors comprise a substantially planar array and are disposed on the surface, and wherein operating the micromirror device to electronically control respective angles of actuatable mirrors of the micromirror device comprises controlling a first set of one or more of the actuatable mirrors to have a first angle relative to the surface during a specified period of time during the first period of time and controlling a second set of one or more of the actuatable mirrors to have a second angle relative to the surface during a specified period of time during the first period of time; imaging light emitted from the target in response to the light from the light source during the first period of time using a second camera to produce a second image of the target, wherein the second camera comprises a plurality of light-sensitive elements disposed on a focal surface of the second camera; and wherein the target is illuminated by the light source via reflection from the first set of one or more actuatable mirrors, wherein the light emitted from the target is directed toward the second camera via reflection from the first set of one or more actuatable mirrors and toward the spatial light modulator via reflection from the second set of one or more actuatable mirrors.
 38. The method of claim 37, wherein operating the micromirror device to control respective angles of actuatable mirrors of the micromirror device during the first period of time comprises controlling, during respective specified periods of time during the first period of time: (i) a plurality of respective first sets of one or more actuatable mirrors to have the first angle relative to the surface and (ii) a plurality of respective second sets of one or more actuatable mirrors to have the second angle relative to the surface, and further comprising: electronically controlling the spatial light modulator during a plurality of further periods of time such that the refractive index of the refractive layer varies spatially across the spatial light modulator; imaging light emitted from the target in response to the light from the light source during the plurality of further periods of time using the second camera to produce respective further images of the target; and imaging light emitted from the target in response to light from the light source during the plurality of further periods of time using the first camera to produce respective further images of the target, wherein determining spectrographic information for a particular region of the target comprises determining spectrographic information based on the first image and the plurality of further images of the target generated by the first camera.
 39. The method of claim 29, further comprising: controlling, using an actuated stage, the location of the target relative to the optical system.
 40. The method of claim 29, wherein the spatial light modulator comprises an array of cells having respective electronically controllable refractive indexes. 